diff --git a/.github/workflows/code_formatting.yml b/.github/workflows/code_formatting.yml
index 81a2715f1b..cab0ae55b2 100644
--- a/.github/workflows/code_formatting.yml
+++ b/.github/workflows/code_formatting.yml
@@ -10,7 +10,7 @@ jobs:
   code-formatting:
     runs-on: ubuntu-22.04
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
     - uses: actions/setup-python@v4
     - name: Install packages
       run: source tools/ci.sh && ci_code_formatting_setup
@@ -22,7 +22,7 @@ jobs:
   code-spelling:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
     - uses: actions/setup-python@v4
     - name: Install packages
       run: source tools/ci.sh && ci_code_spell_setup
diff --git a/.github/workflows/code_size.yml b/.github/workflows/code_size.yml
index 5d955703b6..56097a6d3e 100644
--- a/.github/workflows/code_size.yml
+++ b/.github/workflows/code_size.yml
@@ -20,7 +20,7 @@ jobs:
   build:
     runs-on: ubuntu-20.04
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
       with:
         fetch-depth: 100
     - name: Install packages
diff --git a/.github/workflows/commit_formatting.yml b/.github/workflows/commit_formatting.yml
index 0b27038f2d..a651f8a13a 100644
--- a/.github/workflows/commit_formatting.yml
+++ b/.github/workflows/commit_formatting.yml
@@ -10,7 +10,7 @@ jobs:
   build:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
       with:
         fetch-depth: '100'
     - uses: actions/setup-python@v4
diff --git a/.github/workflows/docs.yml b/.github/workflows/docs.yml
index e9b1700747..afc3166f3d 100644
--- a/.github/workflows/docs.yml
+++ b/.github/workflows/docs.yml
@@ -14,7 +14,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
     - uses: actions/setup-python@v4
     - name: Install Python packages
       run: pip install Sphinx
diff --git a/.github/workflows/examples.yml b/.github/workflows/examples.yml
index 450805a6bd..6613f10662 100644
--- a/.github/workflows/examples.yml
+++ b/.github/workflows/examples.yml
@@ -18,7 +18,7 @@ jobs:
   embedding:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
     - name: Build
       run: make -C examples/embedding -f micropython_embed.mk && make -C examples/embedding
     - name: Run
diff --git a/.github/workflows/mpremote.yml b/.github/workflows/mpremote.yml
index 14aef03e07..5b9465d7fe 100644
--- a/.github/workflows/mpremote.yml
+++ b/.github/workflows/mpremote.yml
@@ -11,7 +11,7 @@ jobs:
   build:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
       with:
         # Setting this to zero means fetch all history and tags,
         # which hatch-vcs can use to discover the version tag.
diff --git a/.github/workflows/mpy_format.yml b/.github/workflows/mpy_format.yml
index 66abb19b81..baa02ce08d 100644
--- a/.github/workflows/mpy_format.yml
+++ b/.github/workflows/mpy_format.yml
@@ -17,7 +17,7 @@ jobs:
   test:
     runs-on: ubuntu-20.04 # use 20.04 to get python2
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
     - name: Install packages
       run: source tools/ci.sh && ci_mpy_format_setup
     - name: Test mpy-tool.py
diff --git a/.github/workflows/ports.yml b/.github/workflows/ports.yml
index fb574ad981..1f262b0ba4 100644
--- a/.github/workflows/ports.yml
+++ b/.github/workflows/ports.yml
@@ -17,6 +17,6 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
     - name: Build ports download metadata
       run: mkdir boards && ./tools/autobuild/build-downloads.py . ./boards
diff --git a/.github/workflows/ports_cc3200.yml b/.github/workflows/ports_cc3200.yml
index b58bc24b58..f178a14058 100644
--- a/.github/workflows/ports_cc3200.yml
+++ b/.github/workflows/ports_cc3200.yml
@@ -21,7 +21,7 @@ jobs:
   build:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
     - name: Install packages
       run: source tools/ci.sh && ci_cc3200_setup
     - name: Build
diff --git a/.github/workflows/ports_esp32.yml b/.github/workflows/ports_esp32.yml
index 2cc9f592bf..9403aa656b 100644
--- a/.github/workflows/ports_esp32.yml
+++ b/.github/workflows/ports_esp32.yml
@@ -21,7 +21,7 @@ jobs:
   build_idf50:
     runs-on: ubuntu-20.04
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
     - name: Install packages
       run: source tools/ci.sh && ci_esp32_idf50_setup
     - name: Build
diff --git a/.github/workflows/ports_esp8266.yml b/.github/workflows/ports_esp8266.yml
index ba89d5e952..5236edf40b 100644
--- a/.github/workflows/ports_esp8266.yml
+++ b/.github/workflows/ports_esp8266.yml
@@ -21,7 +21,7 @@ jobs:
   build:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
     - name: Install packages
       run: source tools/ci.sh && ci_esp8266_setup && ci_esp8266_path >> $GITHUB_PATH
     - name: Build
diff --git a/.github/workflows/ports_mimxrt.yml b/.github/workflows/ports_mimxrt.yml
index d915625341..614d745807 100644
--- a/.github/workflows/ports_mimxrt.yml
+++ b/.github/workflows/ports_mimxrt.yml
@@ -21,7 +21,7 @@ jobs:
   build:
     runs-on: ubuntu-20.04
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
     - name: Install packages
       run: source tools/ci.sh && ci_mimxrt_setup
     - name: Build
diff --git a/.github/workflows/ports_nrf.yml b/.github/workflows/ports_nrf.yml
index 8921121780..d9cffb9778 100644
--- a/.github/workflows/ports_nrf.yml
+++ b/.github/workflows/ports_nrf.yml
@@ -21,7 +21,7 @@ jobs:
   build:
     runs-on: ubuntu-20.04
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
     - name: Install packages
       run: source tools/ci.sh && ci_nrf_setup
     - name: Build
diff --git a/.github/workflows/ports_powerpc.yml b/.github/workflows/ports_powerpc.yml
index a15c4da97f..c41b13e5dd 100644
--- a/.github/workflows/ports_powerpc.yml
+++ b/.github/workflows/ports_powerpc.yml
@@ -21,7 +21,7 @@ jobs:
   build:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
     - name: Install packages
       run: source tools/ci.sh && ci_powerpc_setup
     - name: Build
diff --git a/.github/workflows/ports_qemu-arm.yml b/.github/workflows/ports_qemu-arm.yml
index 93ec4da767..db3cd7871d 100644
--- a/.github/workflows/ports_qemu-arm.yml
+++ b/.github/workflows/ports_qemu-arm.yml
@@ -22,7 +22,7 @@ jobs:
   build_and_test:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
     - name: Install packages
       run: source tools/ci.sh && ci_qemu_arm_setup
     - name: Build and run test suite
diff --git a/.github/workflows/ports_renesas-ra.yml b/.github/workflows/ports_renesas-ra.yml
index 33e17a385a..b1a30c2f11 100644
--- a/.github/workflows/ports_renesas-ra.yml
+++ b/.github/workflows/ports_renesas-ra.yml
@@ -21,7 +21,7 @@ jobs:
   build_renesas_ra_board:
     runs-on: ubuntu-20.04
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
     - name: Install packages
       run: source tools/ci.sh && ci_renesas_ra_setup
     - name: Build
diff --git a/.github/workflows/ports_rp2.yml b/.github/workflows/ports_rp2.yml
index f042ff1151..5741b75d2a 100644
--- a/.github/workflows/ports_rp2.yml
+++ b/.github/workflows/ports_rp2.yml
@@ -21,7 +21,7 @@ jobs:
   build:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
     - name: Install packages
       run: source tools/ci.sh && ci_rp2_setup
     - name: Build
diff --git a/.github/workflows/ports_samd.yml b/.github/workflows/ports_samd.yml
index 9833a2fae2..5bf1826cd1 100644
--- a/.github/workflows/ports_samd.yml
+++ b/.github/workflows/ports_samd.yml
@@ -21,7 +21,7 @@ jobs:
   build:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
     - name: Install packages
       run: source tools/ci.sh && ci_samd_setup
     - name: Build
diff --git a/.github/workflows/ports_stm32.yml b/.github/workflows/ports_stm32.yml
index b278ea862c..0b781a93c1 100644
--- a/.github/workflows/ports_stm32.yml
+++ b/.github/workflows/ports_stm32.yml
@@ -21,7 +21,7 @@ jobs:
   build_pyb:
     runs-on: ubuntu-20.04
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
     - name: Install packages
       run: source tools/ci.sh && ci_stm32_setup
     - name: Build
@@ -30,7 +30,7 @@ jobs:
   build_nucleo:
     runs-on: ubuntu-20.04
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
     - name: Install packages
       run: source tools/ci.sh && ci_stm32_setup
     - name: Build
diff --git a/.github/workflows/ports_teensy.yml b/.github/workflows/ports_teensy.yml
index f129960325..291c8e303c 100644
--- a/.github/workflows/ports_teensy.yml
+++ b/.github/workflows/ports_teensy.yml
@@ -21,7 +21,7 @@ jobs:
   build:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
     - name: Install packages
       run: source tools/ci.sh && ci_teensy_setup
     - name: Build
diff --git a/.github/workflows/ports_unix.yml b/.github/workflows/ports_unix.yml
index 87c58055b9..04dfd78525 100644
--- a/.github/workflows/ports_unix.yml
+++ b/.github/workflows/ports_unix.yml
@@ -23,7 +23,7 @@ jobs:
   minimal:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
     - name: Build
       run: source tools/ci.sh && ci_unix_minimal_build
     - name: Run main test suite
@@ -35,7 +35,7 @@ jobs:
   reproducible:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
     - name: Build with reproducible date
       run: source tools/ci.sh && ci_unix_minimal_build
       env:
@@ -46,7 +46,7 @@ jobs:
   standard:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
     - name: Build
       run: source tools/ci.sh && ci_unix_standard_build
     - name: Run main test suite
@@ -58,7 +58,7 @@ jobs:
   coverage:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
     - name: Install packages
       run: source tools/ci.sh && ci_unix_coverage_setup
     - name: Build
@@ -87,7 +87,7 @@ jobs:
   coverage_32bit:
     runs-on: ubuntu-20.04 # use 20.04 to get libffi-dev:i386
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
     - name: Install packages
       run: source tools/ci.sh && ci_unix_32bit_setup
     - name: Build
@@ -105,7 +105,7 @@ jobs:
   nanbox:
     runs-on: ubuntu-20.04 # use 20.04 to get python2, and libffi-dev:i386
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
     - name: Install packages
       run: source tools/ci.sh && ci_unix_32bit_setup
     - name: Build
@@ -119,7 +119,7 @@ jobs:
   float:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
     - name: Build
       run: source tools/ci.sh && ci_unix_float_build
     - name: Run main test suite
@@ -131,7 +131,7 @@ jobs:
   stackless_clang:
     runs-on: ubuntu-20.04
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
     - name: Install packages
       run: source tools/ci.sh && ci_unix_clang_setup
     - name: Build
@@ -145,7 +145,7 @@ jobs:
   float_clang:
     runs-on: ubuntu-20.04
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
     - name: Install packages
       run: source tools/ci.sh && ci_unix_clang_setup
     - name: Build
@@ -159,7 +159,7 @@ jobs:
   settrace:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
     - name: Build
       run: source tools/ci.sh && ci_unix_settrace_build
     - name: Run main test suite
@@ -171,7 +171,7 @@ jobs:
   settrace_stackless:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
     - name: Build
       run: source tools/ci.sh && ci_unix_settrace_stackless_build
     - name: Run main test suite
@@ -183,7 +183,7 @@ jobs:
   macos:
     runs-on: macos-11.0
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
     - uses: actions/setup-python@v4
       with:
         python-version: '3.8'
@@ -198,7 +198,7 @@ jobs:
   qemu_mips:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
     - name: Install packages
       run: source tools/ci.sh && ci_unix_qemu_mips_setup
     - name: Build
@@ -212,7 +212,7 @@ jobs:
   qemu_arm:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
     - name: Install packages
       run: source tools/ci.sh && ci_unix_qemu_arm_setup
     - name: Build
diff --git a/.github/workflows/ports_webassembly.yml b/.github/workflows/ports_webassembly.yml
index 2e0865662f..880f15ab34 100644
--- a/.github/workflows/ports_webassembly.yml
+++ b/.github/workflows/ports_webassembly.yml
@@ -20,7 +20,7 @@ jobs:
   build:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
     - name: Install packages
       run: source tools/ci.sh && ci_webassembly_setup
     - name: Build
diff --git a/.github/workflows/ports_windows.yml b/.github/workflows/ports_windows.yml
index b31718c591..4b1f4ea791 100644
--- a/.github/workflows/ports_windows.yml
+++ b/.github/workflows/ports_windows.yml
@@ -21,7 +21,7 @@ jobs:
   build:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
     - name: Install packages
       run: source tools/ci.sh && ci_windows_setup
     - name: Build
diff --git a/.github/workflows/ports_zephyr.yml b/.github/workflows/ports_zephyr.yml
index f64401b316..f6f328c927 100644
--- a/.github/workflows/ports_zephyr.yml
+++ b/.github/workflows/ports_zephyr.yml
@@ -20,7 +20,7 @@ jobs:
   build:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
     - name: Install packages
       run: source tools/ci.sh && ci_zephyr_setup
     - name: Install Zephyr
diff --git a/.github/workflows/ruff.yml b/.github/workflows/ruff.yml
index b8e43dc78f..806d95e895 100644
--- a/.github/workflows/ruff.yml
+++ b/.github/workflows/ruff.yml
@@ -5,6 +5,6 @@ jobs:
   ruff:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
     - run: pip install --user ruff
     - run: ruff --format=github .
diff --git a/docs/develop/gettingstarted.rst b/docs/develop/gettingstarted.rst
index c2d3816d42..34ca1c9c63 100644
--- a/docs/develop/gettingstarted.rst
+++ b/docs/develop/gettingstarted.rst
@@ -100,7 +100,7 @@ For the stm32 port, the ARM cross-compiler is required:
 
 .. code-block:: bash
 
-   $ sudo apt-get install arm-none-eabi-gcc arm-none-eabi-binutils arm-none-eabi-newlib
+   $ sudo apt-get install gcc-arm-none-eabi libnewlib-arm-none-eabi
 
 See the `ARM GCC
 toolchain <https://developer.arm.com/downloads/-/arm-gnu-toolchain-downloads>`_
@@ -228,7 +228,7 @@ You can also specify which board to use:
 .. code-block:: bash
 
    $ cd ports/stm32
-   $ make submodules
+   $ make BOARD=<board> submodules
    $ make BOARD=<board>
 
 See `ports/stm32/boards <https://github.com/micropython/micropython/tree/master/ports/stm32/boards>`_
diff --git a/docs/esp32/tutorial/img/mem32_gpio_output.jpg b/docs/esp32/tutorial/img/mem32_gpio_output.jpg
new file mode 100755
index 0000000000..5544202871
Binary files /dev/null and b/docs/esp32/tutorial/img/mem32_gpio_output.jpg differ
diff --git a/docs/esp32/tutorial/peripheral_access.rst b/docs/esp32/tutorial/peripheral_access.rst
index 3304c341de..ecdec101f7 100644
--- a/docs/esp32/tutorial/peripheral_access.rst
+++ b/docs/esp32/tutorial/peripheral_access.rst
@@ -42,3 +42,83 @@ for this:
 
 The MCPWM0 peripheral is in bit position 17 of the above two registers, hence
 the value of ``DPORT_PWM0_CLK_EN``.
+
+Synchronous access to pins directly via registers
+-------------------------------------------------
+
+The following code shows how to access pins directly via registers.  It has been
+tested on a generic ESP32 board.  It configures pins 16, 17, 32 and 33 in output
+mode via registers, and switches pin output values via registers.  Pins 16 and
+17 are switched simultaneously.
+
+.. code-block:: python3
+
+    from micropython import const
+    from machine import mem32, Pin
+
+    GPIO_OUT_REG = const(0x3FF44004)  # GPIO 0-31 output register
+    GPIO_OUT1_REG = const(0x3FF44010)  # GPIO 32-39 output register
+
+    GPIO_ENABLE_REG = const(0x3FF44020)  # GPIO 0-31 output enable register
+    GPIO_ENABLE1_REG = const(0x3FF4402C)  # GPIO 32-39 output enable register
+
+    M16 = 1 << 16  # Pin(16) bit mask
+    M17 = 1 << 17  # Pin(17) bit mask
+
+    M32 = 1 << (32-32)  # Pin(32) bit mask
+    M33 = 1 << (33-32)  # Pin(33) bit mask
+
+    # Enable pin output mode like
+    # p16 = Pin(16, mode=Pin.OUT)
+    # p17 = Pin(17, mode=Pin.OUT)
+    # p32 = Pin(32, mode=Pin.OUT)
+    # p33 = Pin(33, mode=Pin.OUT)
+    mem32[GPIO_ENABLE_REG] = mem32[GPIO_ENABLE_REG] | M16 | M17
+    mem32[GPIO_ENABLE1_REG] = mem32[GPIO_ENABLE1_REG] | M32 | M33
+
+    print(hex(mem32[GPIO_OUT_REG]), hex(mem32[GPIO_OUT1_REG]))
+
+    # Set outputs to 1 like
+    # p16(1)
+    # p17(1)
+    # p32(1)
+    # p33(1)
+    mem32[GPIO_OUT_REG] = mem32[GPIO_OUT_REG] | M16 | M17
+    mem32[GPIO_OUT1_REG] = mem32[GPIO_OUT1_REG] | M32 | M33
+
+    print(hex(mem32[GPIO_OUT_REG]), hex(mem32[GPIO_OUT1_REG]))
+
+    # Set outputs to 0 like
+    # p16(0)
+    # p17(0)
+    # p32(0)
+    # p33(0)
+    mem32[GPIO_OUT_REG] = mem32[GPIO_OUT_REG] & ~(M16 | M17)
+    mem32[GPIO_OUT1_REG] = mem32[GPIO_OUT1_REG] & ~(M32 | M33)
+
+    print(hex(mem32[GPIO_OUT_REG]), hex(mem32[GPIO_OUT1_REG]))
+
+    while True:
+        # Set outputs to 1
+        mem32[GPIO_OUT_REG] = mem32[GPIO_OUT_REG] | M16 | M17
+        mem32[GPIO_OUT1_REG] = mem32[GPIO_OUT1_REG] | M32 | M33
+
+        # Set outputs to 0
+        mem32[GPIO_OUT_REG] = mem32[GPIO_OUT_REG] & ~(M16 | M17)
+        mem32[GPIO_OUT1_REG] = mem32[GPIO_OUT1_REG] & ~(M32 | M33)
+
+
+Output is::
+
+    0x0 0x0
+    0x30000 0x3
+    0x0 0x0
+
+Pins 16 and 17 are switched synchronously:
+
+.. image:: img/mem32_gpio_output.jpg
+
+Same image on pins 32 and 33.
+
+Note that pins 34-36 and 39 are inputs only. Also pins 1 and 3 are Tx, Rx of the REPL UART,
+pins 6-11 are connected to the built-in SPI flash.
diff --git a/docs/library/deflate.rst b/docs/library/deflate.rst
index 9752af5925..fad5778705 100644
--- a/docs/library/deflate.rst
+++ b/docs/library/deflate.rst
@@ -41,9 +41,15 @@ Classes
    to 1024 bytes. Valid values are ``5`` to ``15`` inclusive (corresponding to
    window sizes of 32 to 32k bytes).
 
-   If *wbits* is set to ``0`` (the default), then a window size of 256 bytes
-   will be used (corresponding to *wbits* set to ``8``), except when
-   :ref:`decompressing a zlib stream <deflate_wbits_zlib>`.
+   If *wbits* is set to ``0`` (the default), then for compression a window size
+   of 256 bytes will be used (as if *wbits* was set to 8). For decompression, it
+   depends on the format:
+
+   * ``RAW`` will use 256 bytes (corresponding to *wbits* set to 8).
+   * ``ZLIB`` (or ``AUTO`` with zlib detected) will use the value from the zlib
+     header.
+   * ``GZIP`` (or ``AUTO`` with gzip detected) will use 32 kilobytes
+     (corresponding to *wbits* set to 15).
 
    See the :ref:`window size <deflate_wbits>` notes below for more information
    about the window size, zlib, and gzip streams.
@@ -134,44 +140,43 @@ Deflate window size
 -------------------
 
 The window size limits how far back in the stream the (de)compressor can
-reference. Increasing the window size will improve compression, but will
-require more memory.
+reference. Increasing the window size will improve compression, but will require
+more memory and make the compressor slower.
 
-However, just because a given window size is used for compression, this does not
-mean that the stream will require the same size window for decompression, as
-the stream may not reference data as far back as the window allows (for example,
-if the length of the input is smaller than the window size).
+If an input stream was compressed a given window size, then `DeflateIO`
+using a smaller window size will fail mid-way during decompression with
+:exc:`OSError`, but only if a back-reference actually refers back further
+than the decompressor's window size. This means it may be possible to decompress
+with a smaller window size. For example, this would trivially be the case if the
+original uncompressed data is shorter than the window size.
 
-If the decompressor uses a smaller window size than necessary for the input data
-stream, it will fail mid-way through decompression with :exc:`OSError`.
+Decompression
+~~~~~~~~~~~~~
 
-.. _deflate_wbits_zlib:
+The zlib format includes a header which specifies the window size that was used
+to compress the data. This indicates the maximum window size required to
+decompress this stream. If this header value is less than the specified *wbits*
+value (or if *wbits* is unset), then the header value will be used.
 
-The zlib format includes a header which specifies the window size used to
-compress the data (which due to the above, may be larger than the size required
-for the decompressor).
+The gzip format does not include the window size in the header, and assumes that
+all gzip compressors (e.g. the ``gzip`` utility, or CPython's implementation of
+:class:`gzip.GzipFile`) use the maximum window size of 32kiB. For this reason,
+if the *wbits* parameter is not set, the decompressor will use a 32 kiB window
+size (corresponding to *wbits* set to 15). This means that to be able to
+decompress an arbitrary gzip stream, you must have at least this much RAM
+available. If you control the source data, consider instead using the zlib
+format with a smaller window size.
 
-If this header value is lower than the specified *wbits* value, then the header
-value will be used instead in order to reduce the memory allocation size. If
-the *wbits* parameter is zero (the default), then the header value will only be
-used if it is less than the maximum value of ``15`` (which is default value
-used by most compressors [#f1]_).
+The raw format has no header and therefore does not include any information
+about the window size. If *wbits* is not set, then it will default to a window
+size of 256 bytes, which may not be large enough for a given stream. Therefore
+it is recommended that you should always explicitly set *wbits* if using the raw
+format.
 
-In other words, if the source zlib stream has been compressed with a custom window
-size (i.e. less than ``15``), then using the default *wbits* parameter of zero
-will decompress any such stream.
+Compression
+~~~~~~~~~~~
 
-The gzip file format does not include the window size in the header.
-Additionally, most compressor libraries (including CPython's implementation
-of :class:`gzip.GzipFile`) will default to the maximum possible window size.
-This makes it difficult to decompress most gzip streams on MicroPython unless
-your board has a lot of free RAM.
-
-If you control the source of the compressed data, then prefer to use the zlib
-format, with a window size that is suitable for your target device.
-
-.. rubric:: Footnotes
-
-.. [#f1] The assumption here is that if the header value is the default used by
-   most compressors, then nothing is known about the likely required window
-   size and we should ignore it.
+For compression, MicroPython will default to a window size of 256 bytes for all
+formats. This provides a reasonable amount of compression with minimal memory
+usage and fast compression time, and will generate output that will work with
+any decompressor.
diff --git a/docs/library/esp32.rst b/docs/library/esp32.rst
index efdd6c1be2..d6b4051a2f 100644
--- a/docs/library/esp32.rst
+++ b/docs/library/esp32.rst
@@ -51,13 +51,20 @@ Functions
     buffers and other data. This data is useful to get a sense of how much memory
     is available to ESP-IDF and the networking stack in particular. It may shed
     some light on situations where ESP-IDF operations fail due to allocation failures.
-    The information returned is *not* useful to troubleshoot Python allocation failures,
-    use `micropython.mem_info()` instead.
 
     The capabilities parameter corresponds to ESP-IDF's ``MALLOC_CAP_XXX`` values but the
     two most useful ones are predefined as `esp32.HEAP_DATA` for data heap regions and
     `esp32.HEAP_EXEC` for executable regions as used by the native code emitter.
 
+    Free IDF heap memory in the `esp32.HEAP_DATA` region is available to be
+    automatically added to the MicroPython heap to prevent a MicroPython
+    allocation from failing. However, the information returned here is otherwise
+    *not* useful to troubleshoot Python allocation failures, use
+    `micropython.mem_info()` instead. The "max new split" value in
+    `micropython.mem_info()` output corresponds to the largest free block of
+    ESP-IDF heap that could be automatically added on demand to the MicroPython
+    heap.
+
     The return value is a list of 4-tuples, where each 4-tuple corresponds to one heap
     and contains: the total bytes, the free bytes, the largest free block, and
     the minimum free seen over time.
@@ -107,6 +114,11 @@ methods to enable over-the-air (OTA) updates.
 
     Sets the partition as the boot partition.
 
+    .. note:: Do not enter :func:`deepsleep<machine.deepsleep>` after changing
+       the OTA boot partition, without first performing a hard
+       :func:`reset<machine.reset>` or power cycle. This ensures the bootloader
+       will validate the new image before booting.
+
 .. method:: Partition.get_next_update()
 
     Gets the next update partition after this one, and returns a new Partition object.
diff --git a/docs/library/index.rst b/docs/library/index.rst
index ae5d3e7d71..4a7f78ecf3 100644
--- a/docs/library/index.rst
+++ b/docs/library/index.rst
@@ -71,6 +71,7 @@ library.
    json.rst
    math.rst
    os.rst
+   platform.rst
    random.rst
    re.rst
    select.rst
diff --git a/docs/library/neopixel.rst b/docs/library/neopixel.rst
index 543f258812..edcbc9345c 100644
--- a/docs/library/neopixel.rst
+++ b/docs/library/neopixel.rst
@@ -9,9 +9,7 @@ This module provides a driver for WS2818 / NeoPixel LEDs.
 .. note:: This module is only included by default on the ESP8266, ESP32 and RP2
    ports. On STM32 / Pyboard and others, you can either install the
    ``neopixel`` package using :term:`mip`, or you can download the module
-   directly from
-   <https://raw.githubusercontent.com/micropython/micropython-lib/master/micropython/drivers/led/neopixel/neopixel.py>`_
-   and copy it to the filesystem.
+   directly from :term:`micropython-lib` and copy it to the filesystem.
 
 class NeoPixel
 --------------
diff --git a/docs/library/network.rst b/docs/library/network.rst
index b13c84123c..a14d6192ea 100644
--- a/docs/library/network.rst
+++ b/docs/library/network.rst
@@ -171,8 +171,8 @@ The following are functions available in the network module.
 
 .. function:: hostname([name])
 
-    Get or set the hostname that will identify this device on the network. It is
-    applied to all interfaces.
+    Get or set the hostname that will identify this device on the network. It will
+    be used by all interfaces.
 
     This hostname is used for:
      * Sending to the DHCP server in the client request. (If using DHCP)
@@ -182,6 +182,12 @@ The following are functions available in the network module.
     If the function is called without parameters, it returns the current
     hostname.
 
+    A change in hostname is typically only applied during connection. For DHCP
+    this is because the hostname is part of the DHCP client request, and the
+    implementation of mDNS in most ports only initialises the hostname once
+    during connection. For this reason, you must set the hostname before
+    activating/connecting your network interfaces.
+
     The default hostname is typically the name of the board.
 
 .. function:: phy_mode([mode])
diff --git a/docs/library/platform.rst b/docs/library/platform.rst
new file mode 100644
index 0000000000..c091477d84
--- /dev/null
+++ b/docs/library/platform.rst
@@ -0,0 +1,38 @@
+:mod:`platform` -- access to underlying platform’s identifying data
+===================================================================
+
+.. module:: platform
+   :synopsis: access to underlying platform’s identifying data
+
+|see_cpython_module| :mod:`python:platform`.
+
+This module tries to retrieve as much platform-identifying data as possible. It
+makes this information available via function APIs.
+
+Functions
+---------
+
+.. function:: platform()
+
+   Returns a string identifying the underlying platform. This string is composed
+   of several substrings in the following order, delimited by dashes (``-``):
+
+   - the name of the platform system (e.g. Unix, Windows or MicroPython)
+   - the MicroPython version
+   - the architecture of the platform
+   - the version of the underlying platform
+   - the concatenation of the name of the libc that MicroPython is linked to
+     and its corresponding version.
+
+   For example, this could be
+   ``"MicroPython-1.20.0-xtensa-IDFv4.2.4-with-newlib3.0.0"``.
+
+.. function:: python_compiler()
+
+   Returns a string identifying the compiler used for compiling MicroPython.
+
+.. function:: libc_ver()
+
+   Returns a tuple of strings *(lib, version)*, where *lib* is the name of the
+   libc that MicroPython is linked to, and *version* the corresponding version
+   of this libc.
diff --git a/docs/library/stm.rst b/docs/library/stm.rst
index a181d6044c..970ab18834 100644
--- a/docs/library/stm.rst
+++ b/docs/library/stm.rst
@@ -102,3 +102,39 @@ the second CPU, the RF core.
     Execute a HCI command on the SYS channel.  The execution is synchronous.
 
     Returns a bytes object with the result of the SYS command.
+
+Functions specific to STM32WLxx MCUs
+------------------------------------
+
+These functions are available on STM32WLxx microcontrollers, and interact with
+the integrated "SUBGHZ" radio modem peripheral.
+
+.. function:: subghz_cs(level)
+
+   Sets the internal SPI CS pin attached to the radio peripheral. The ``level``
+   argument is active-low: a truthy value means "CS pin high" and de-asserts the
+   signal, a falsey value means "CS pin low" and asserts the signal.
+
+   The internal-only SPI bus corresponding to this CS signal can be instantiated
+   using :ref:`machine.SPI()<machine.SPI>` ``id`` value ``"SUBGHZ"``.
+
+.. function:: subghz_irq(handler)
+
+   Sets the internal SUBGHZ radio interrupt handler to the provided
+   function. The handler function is called as a "hard" interrupt in response to
+   radio peripheral interrupts. See :ref:`isr_rules` for more information about
+   interrupt handlers in MicroPython.
+
+   Calling this function with the handler argument set to None disables the IRQ.
+
+   Due to a hardware limitation, each time this IRQ fires MicroPython disables
+   it before calling the handler. In order to receive another interrupt, Python
+   code should call ``subghz_irq()`` to set the handler again. This has the side
+   effect of re-enabling the IRQ.
+
+.. function:: subghz_is_busy()
+
+   Return a ``bool`` corresponding to the internal "RFBUSYS" signal from the
+   radio peripheral. Before sending a new command to the radio over SPI then
+   this function should be polled until it returns ``False``, to confirm the
+   busy signal is de-asserted.
diff --git a/drivers/cyw43/cywbt.c b/drivers/cyw43/cywbt.c
index 006fd28e90..bc6674ea2e 100644
--- a/drivers/cyw43/cywbt.c
+++ b/drivers/cyw43/cywbt.c
@@ -29,8 +29,6 @@
 
 #include "py/runtime.h"
 #include "py/mphal.h"
-#include "pin_static_af.h"
-#include "uart.h"
 #include "extmod/mpbthci.h"
 
 #if MICROPY_PY_NETWORK_CYW43
@@ -38,33 +36,41 @@
 #include "lib/cyw43-driver/src/cyw43_config.h"
 #include "lib/cyw43-driver/firmware/cyw43_btfw_4343A1.h"
 
-// Provided by the port.
-extern pyb_uart_obj_t mp_bluetooth_hci_uart_obj;
-
 // Provided by the port, and also possibly shared with the stack.
 extern uint8_t mp_bluetooth_hci_cmd_buf[4 + 256];
 
 /******************************************************************************/
 // CYW BT HCI low-level driver
 
+#ifdef CYW43_PIN_BT_CTS
+// This code is not portable and currently only builds on stm32 port.
+
+#include "pin_static_af.h"
+#include "uart.h"
+
+// Provided by the port.
+extern pyb_uart_obj_t mp_bluetooth_hci_uart_obj;
+
 STATIC void cywbt_wait_cts_low(void) {
-    mp_hal_pin_config(pyb_pin_BT_CTS, MP_HAL_PIN_MODE_INPUT, MP_HAL_PIN_PULL_UP, 0);
+    mp_hal_pin_config(CYW43_PIN_BT_CTS, MP_HAL_PIN_MODE_INPUT, MP_HAL_PIN_PULL_UP, 0);
     for (int i = 0; i < 200; ++i) {
-        if (mp_hal_pin_read(pyb_pin_BT_CTS) == 0) {
+        if (mp_hal_pin_read(CYW43_PIN_BT_CTS) == 0) {
             break;
         }
         mp_hal_delay_ms(1);
     }
-    mp_hal_pin_config_alt(pyb_pin_BT_CTS, MP_HAL_PIN_MODE_ALT, MP_HAL_PIN_PULL_UP, AF_FN_UART, mp_bluetooth_hci_uart_obj.uart_id);
+    mp_hal_pin_config_alt(CYW43_PIN_BT_CTS, MP_HAL_PIN_MODE_ALT,
+        MP_HAL_PIN_PULL_UP, AF_FN_UART, mp_bluetooth_hci_uart_obj.uart_id);
 }
+#endif
 
 STATIC int cywbt_hci_cmd_raw(size_t len, uint8_t *buf) {
-    uart_tx_strn(&mp_bluetooth_hci_uart_obj, (void*)buf, len);
-    for (int i = 0; i < 6; ++i) {
-        while (!uart_rx_any(&mp_bluetooth_hci_uart_obj)) {
+    mp_bluetooth_hci_uart_write((void *)buf, len);
+    for (int c, i = 0; i < 6; ++i) {
+        while ((c = mp_bluetooth_hci_uart_readchar()) == -1) {
             MICROPY_EVENT_POLL_HOOK
         }
-        buf[i] = uart_rx_char(&mp_bluetooth_hci_uart_obj);
+        buf[i] = c;
     }
 
     // expect a command complete event (event 0x0e)
@@ -80,11 +86,11 @@ STATIC int cywbt_hci_cmd_raw(size_t len, uint8_t *buf) {
         */
 
     int sz = buf[2] - 3;
-    for (int i = 0; i < sz; ++i) {
-        while (!uart_rx_any(&mp_bluetooth_hci_uart_obj)) {
+    for (int c, i = 0; i < sz; ++i) {
+        while ((c = mp_bluetooth_hci_uart_readchar()) == -1) {
             MICROPY_EVENT_POLL_HOOK
         }
-        buf[i] = uart_rx_char(&mp_bluetooth_hci_uart_obj);
+        buf[i] = c;
     }
 
     return 0;
@@ -150,12 +156,15 @@ STATIC int cywbt_download_firmware(const uint8_t *firmware) {
 
     // RF switch must select high path during BT patch boot
     #if MICROPY_HW_ENABLE_RF_SWITCH
-    mp_hal_pin_config(pyb_pin_WL_GPIO_1, MP_HAL_PIN_MODE_INPUT, MP_HAL_PIN_PULL_UP, 0);
+    mp_hal_pin_config(CYW43_PIN_WL_GPIO_1, MP_HAL_PIN_MODE_INPUT, MP_HAL_PIN_PULL_UP, 0);
     #endif
     mp_hal_delay_ms(10); // give some time for CTS to go high
+    #ifdef CYW43_PIN_BT_CTS
     cywbt_wait_cts_low();
+    #endif
     #if MICROPY_HW_ENABLE_RF_SWITCH
-    mp_hal_pin_config(pyb_pin_WL_GPIO_1, MP_HAL_PIN_MODE_INPUT, MP_HAL_PIN_PULL_DOWN, 0); // Select chip antenna (could also select external)
+    // Select chip antenna (could also select external)
+    mp_hal_pin_config(CYW43_PIN_WL_GPIO_1, MP_HAL_PIN_MODE_INPUT, MP_HAL_PIN_PULL_DOWN, 0);
     #endif
 
     mp_bluetooth_hci_uart_set_baudrate(115200);
@@ -168,25 +177,33 @@ STATIC int cywbt_download_firmware(const uint8_t *firmware) {
 int mp_bluetooth_hci_controller_init(void) {
     // This is called immediately after the UART is initialised during stack initialisation.
 
-    mp_hal_pin_output(pyb_pin_BT_REG_ON);
-    mp_hal_pin_low(pyb_pin_BT_REG_ON);
-    mp_hal_pin_input(pyb_pin_BT_HOST_WAKE);
-    mp_hal_pin_output(pyb_pin_BT_DEV_WAKE);
-    mp_hal_pin_low(pyb_pin_BT_DEV_WAKE);
+    mp_hal_pin_output(CYW43_PIN_BT_REG_ON);
+    mp_hal_pin_low(CYW43_PIN_BT_REG_ON);
+    #ifdef CYW43_PIN_BT_HOST_WAKE
+    mp_hal_pin_input(CYW43_PIN_BT_HOST_WAKE);
+    #endif
+    #ifdef CYW43_PIN_BT_DEV_WAKE
+    mp_hal_pin_output(CYW43_PIN_BT_DEV_WAKE);
+    mp_hal_pin_low(CYW43_PIN_BT_DEV_WAKE);
+    #endif
 
     #if MICROPY_HW_ENABLE_RF_SWITCH
     // TODO don't select antenna if wifi is enabled
-    mp_hal_pin_config(pyb_pin_WL_GPIO_4, MP_HAL_PIN_MODE_OUTPUT, MP_HAL_PIN_PULL_NONE, 0); // RF-switch power
-    mp_hal_pin_high(pyb_pin_WL_GPIO_4); // Turn the RF-switch on
+    mp_hal_pin_config(CYW43_PIN_WL_GPIO_4, MP_HAL_PIN_MODE_OUTPUT, MP_HAL_PIN_PULL_NONE, 0); // RF-switch power
+    mp_hal_pin_high(CYW43_PIN_WL_GPIO_4); // Turn the RF-switch on
     #endif
 
     uint8_t buf[256];
 
-    mp_hal_pin_low(pyb_pin_BT_REG_ON);
+    mp_hal_pin_low(CYW43_PIN_BT_REG_ON);
     mp_bluetooth_hci_uart_set_baudrate(115200);
     mp_hal_delay_ms(100);
-    mp_hal_pin_high(pyb_pin_BT_REG_ON);
+    mp_hal_pin_high(CYW43_PIN_BT_REG_ON);
+    #ifdef CYW43_PIN_BT_CTS
     cywbt_wait_cts_low();
+    #else
+    mp_hal_delay_ms(100);
+    #endif
 
     // Reset
     cywbt_hci_cmd(0x03, 0x0003, 0, NULL);
@@ -197,7 +214,7 @@ int mp_bluetooth_hci_controller_init(void) {
     mp_bluetooth_hci_uart_set_baudrate(MICROPY_HW_BLE_UART_BAUDRATE_DOWNLOAD_FIRMWARE);
     #endif
 
-    cywbt_download_firmware((const uint8_t*)&cyw43_btfw_4343A1[0]);
+    cywbt_download_firmware((const uint8_t *)&cyw43_btfw_4343A1[0]);
 
     // Reset
     cywbt_hci_cmd(0x03, 0x0003, 0, NULL);
@@ -219,31 +236,33 @@ int mp_bluetooth_hci_controller_init(void) {
     // cywbt_hci_cmd(0x03, 0x0013, 248, buf);
 
     // Configure sleep mode
-    cywbt_hci_cmd(0x3f, 0x27, 12, (const uint8_t*)"\x01\x02\x02\x00\x00\x00\x01\x00\x00\x00\x00\x00");
+    cywbt_hci_cmd(0x3f, 0x27, 12, (const uint8_t *)"\x01\x02\x02\x00\x00\x00\x01\x00\x00\x00\x00\x00");
 
     // HCI_Write_LE_Host_Support
-    cywbt_hci_cmd(3, 109, 2, (const uint8_t*)"\x01\x00");
+    cywbt_hci_cmd(3, 109, 2, (const uint8_t *)"\x01\x00");
 
-    mp_hal_pin_high(pyb_pin_BT_DEV_WAKE); // let sleep
+    #ifdef CYW43_PIN_BT_DEV_WAKE
+    mp_hal_pin_high(CYW43_PIN_BT_DEV_WAKE); // let sleep
+    #endif
 
     return 0;
 }
 
 int mp_bluetooth_hci_controller_deinit(void) {
-    mp_hal_pin_low(pyb_pin_BT_REG_ON);
+    mp_hal_pin_low(CYW43_PIN_BT_REG_ON);
 
     return 0;
 }
 
-#ifdef pyb_pin_BT_DEV_WAKE
+#ifdef CYW43_PIN_BT_DEV_WAKE
 STATIC uint32_t bt_sleep_ticks;
 #endif
 
 int mp_bluetooth_hci_controller_sleep_maybe(void) {
-    #ifdef pyb_pin_BT_DEV_WAKE
-    if (mp_hal_pin_read(pyb_pin_BT_DEV_WAKE) == 0) {
+    #ifdef CYW43_PIN_BT_DEV_WAKE
+    if (mp_hal_pin_read(CYW43_PIN_BT_DEV_WAKE) == 0) {
         if (mp_hal_ticks_ms() - bt_sleep_ticks > 500) {
-            mp_hal_pin_high(pyb_pin_BT_DEV_WAKE); // let sleep
+            mp_hal_pin_high(CYW43_PIN_BT_DEV_WAKE); // let sleep
         }
     }
     #endif
@@ -251,8 +270,8 @@ int mp_bluetooth_hci_controller_sleep_maybe(void) {
 }
 
 bool mp_bluetooth_hci_controller_woken(void) {
-    #ifdef pyb_pin_BT_HOST_WAKE
-    bool host_wake = mp_hal_pin_read(pyb_pin_BT_HOST_WAKE);
+    #ifdef CYW43_PIN_BT_HOST_WAKE
+    bool host_wake = mp_hal_pin_read(CYW43_PIN_BT_HOST_WAKE);
     /*
     // this is just for info/tracing purposes
     static bool last_host_wake = false;
@@ -268,11 +287,11 @@ bool mp_bluetooth_hci_controller_woken(void) {
 }
 
 int mp_bluetooth_hci_controller_wakeup(void) {
-    #ifdef pyb_pin_BT_DEV_WAKE
+    #ifdef CYW43_PIN_BT_DEV_WAKE
     bt_sleep_ticks = mp_hal_ticks_ms();
 
-    if (mp_hal_pin_read(pyb_pin_BT_DEV_WAKE) == 1) {
-        mp_hal_pin_low(pyb_pin_BT_DEV_WAKE); // wake up
+    if (mp_hal_pin_read(CYW43_PIN_BT_DEV_WAKE) == 1) {
+        mp_hal_pin_low(CYW43_PIN_BT_DEV_WAKE); // wake up
         // Use delay_us rather than delay_ms to prevent running the scheduler (which
         // might result in more BLE operations).
         mp_hal_delay_us(5000); // can't go lower than this
diff --git a/examples/asmled.py b/examples/asmled.py
index 09a06c184a..4ff35dfdf8 100644
--- a/examples/asmled.py
+++ b/examples/asmled.py
@@ -1,5 +1,9 @@
 # flash LED #1 using inline assembler
 # this version is overly verbose and uses word stores
+#
+# ruff: noqa: F821 - @asm_thumb decorator adds names to function scope
+
+
 @micropython.asm_thumb
 def flash_led(r0):
     movw(r1, (stm.GPIOA + stm.GPIO_BSRRL) & 0xFFFF)
diff --git a/examples/asmsum.py b/examples/asmsum.py
index f2c7f285ba..2d8c2b2c99 100644
--- a/examples/asmsum.py
+++ b/examples/asmsum.py
@@ -1,3 +1,6 @@
+# ruff: noqa: F821 - @asm_thumb decorator adds names to function scope
+
+
 @micropython.asm_thumb
 def asm_sum_words(r0, r1):
     # r0 = len
diff --git a/examples/bluetooth/ble_advertising.py b/examples/bluetooth/ble_advertising.py
index eed527f55d..2fe17d640b 100644
--- a/examples/bluetooth/ble_advertising.py
+++ b/examples/bluetooth/ble_advertising.py
@@ -1,5 +1,9 @@
 # Helpers for generating BLE advertising payloads.
 
+# A more fully-featured (and easier to use) version of this is implemented in
+# aioble. This code is provided just as a basic example. See
+# https://github.com/micropython/micropython-lib/tree/master/micropython/bluetooth/aioble
+
 from micropython import const
 import struct
 import bluetooth
@@ -19,6 +23,8 @@ _ADV_TYPE_UUID32_MORE = const(0x4)
 _ADV_TYPE_UUID128_MORE = const(0x6)
 _ADV_TYPE_APPEARANCE = const(0x19)
 
+_ADV_MAX_PAYLOAD = const(31)
+
 
 # Generate a payload to be passed to gap_advertise(adv_data=...).
 def advertising_payload(limited_disc=False, br_edr=False, name=None, services=None, appearance=0):
@@ -50,6 +56,9 @@ def advertising_payload(limited_disc=False, br_edr=False, name=None, services=No
     if appearance:
         _append(_ADV_TYPE_APPEARANCE, struct.pack("<h", appearance))
 
+    if len(payload) > _ADV_MAX_PAYLOAD:
+        raise ValueError("advertising payload too large")
+
     return payload
 
 
diff --git a/examples/bluetooth/ble_bonding_peripheral.py b/examples/bluetooth/ble_bonding_peripheral.py
index bd7596dbcb..c3ae5f262a 100644
--- a/examples/bluetooth/ble_bonding_peripheral.py
+++ b/examples/bluetooth/ble_bonding_peripheral.py
@@ -4,6 +4,11 @@
 # any connected central every 10 seconds.
 #
 # Work-in-progress demo of implementing bonding and passkey auth.
+#
+# This example demonstrates the low-level bluetooth module. For most
+# applications, we recommend using the higher-level aioble library, which
+# includes an implementation of the secret store. See
+# https://github.com/micropython/micropython-lib/tree/master/micropython/bluetooth/aioble
 
 import bluetooth
 import random
diff --git a/examples/bluetooth/ble_simple_central.py b/examples/bluetooth/ble_simple_central.py
index 3c0cf2a0d4..caf6333472 100644
--- a/examples/bluetooth/ble_simple_central.py
+++ b/examples/bluetooth/ble_simple_central.py
@@ -1,6 +1,11 @@
 # This example finds and connects to a peripheral running the
 # UART service (e.g. ble_simple_peripheral.py).
 
+# This example demonstrates the low-level bluetooth module. For most
+# applications, we recommend using the higher-level aioble library which takes
+# care of all IRQ handling and connection management. See
+# https://github.com/micropython/micropython-lib/tree/master/micropython/bluetooth/aioble
+
 import bluetooth
 import random
 import struct
diff --git a/examples/bluetooth/ble_simple_peripheral.py b/examples/bluetooth/ble_simple_peripheral.py
index 0ebe431764..bdb5ed88c7 100644
--- a/examples/bluetooth/ble_simple_peripheral.py
+++ b/examples/bluetooth/ble_simple_peripheral.py
@@ -1,5 +1,10 @@
 # This example demonstrates a UART periperhal.
 
+# This example demonstrates the low-level bluetooth module. For most
+# applications, we recommend using the higher-level aioble library which takes
+# care of all IRQ handling and connection management. See
+# https://github.com/micropython/micropython-lib/tree/master/micropython/bluetooth/aioble
+
 import bluetooth
 import random
 import struct
diff --git a/examples/bluetooth/ble_temperature.py b/examples/bluetooth/ble_temperature.py
index e6378ebee7..acd77127ad 100644
--- a/examples/bluetooth/ble_temperature.py
+++ b/examples/bluetooth/ble_temperature.py
@@ -3,6 +3,12 @@
 # The sensor's local value updates every second, and it will notify
 # any connected central every 10 seconds.
 
+# This example demonstrates the low-level bluetooth module. For most
+# applications, we recommend using the higher-level aioble library which takes
+# care of all IRQ handling and connection management. See
+# https://github.com/micropython/micropython-lib/tree/master/micropython/bluetooth/aioble
+# and in particular the temp_sensor.py example included with aioble.
+
 import bluetooth
 import random
 import struct
diff --git a/examples/bluetooth/ble_temperature_central.py b/examples/bluetooth/ble_temperature_central.py
index afa914672c..fe1c70636f 100644
--- a/examples/bluetooth/ble_temperature_central.py
+++ b/examples/bluetooth/ble_temperature_central.py
@@ -1,5 +1,11 @@
 # This example finds and connects to a BLE temperature sensor (e.g. the one in ble_temperature.py).
 
+# This example demonstrates the low-level bluetooth module. For most
+# applications, we recommend using the higher-level aioble library which takes
+# care of all IRQ handling and connection management. See
+# https://github.com/micropython/micropython-lib/tree/master/micropython/bluetooth/aioble
+# and in particular the temp_client.py example included with aioble.
+
 import bluetooth
 import random
 import struct
diff --git a/examples/bluetooth/ble_uart_peripheral.py b/examples/bluetooth/ble_uart_peripheral.py
index b4e352be9f..0de4fe2ed4 100644
--- a/examples/bluetooth/ble_uart_peripheral.py
+++ b/examples/bluetooth/ble_uart_peripheral.py
@@ -1,5 +1,10 @@
 # This example demonstrates a peripheral implementing the Nordic UART Service (NUS).
 
+# This example demonstrates the low-level bluetooth module. For most
+# applications, we recommend using the higher-level aioble library which takes
+# care of all IRQ handling and connection management. See
+# https://github.com/micropython/micropython-lib/tree/master/micropython/bluetooth/aioble
+
 import bluetooth
 from ble_advertising import advertising_payload
 
diff --git a/examples/bluetooth/ble_uart_repl.py b/examples/bluetooth/ble_uart_repl.py
index 7d92c1f318..5812a5cc13 100644
--- a/examples/bluetooth/ble_uart_repl.py
+++ b/examples/bluetooth/ble_uart_repl.py
@@ -7,6 +7,7 @@ import bluetooth
 import io
 import os
 import micropython
+from micropython import const
 import machine
 
 from ble_uart_peripheral import BLEUART
diff --git a/examples/hwapi/hwconfig_z_96b_carbon.py b/examples/hwapi/hwconfig_z_96b_carbon.py
index 97fd57a07f..d4f98139bc 100644
--- a/examples/hwapi/hwconfig_z_96b_carbon.py
+++ b/examples/hwapi/hwconfig_z_96b_carbon.py
@@ -1,4 +1,4 @@
-from machine import Signal
+from machine import Pin, Signal
 
 # 96Boards Carbon board
 # USR1 - User controlled led, connected to PD2
diff --git a/examples/natmod/README.md b/examples/natmod/README.md
new file mode 100644
index 0000000000..0cc4010ef4
--- /dev/null
+++ b/examples/natmod/README.md
@@ -0,0 +1,74 @@
+# Dynamic Native Modules
+
+Dynamic Native Modules are .mpy files that contain native machine code from a
+language other than Python. For more info see [the documentation]
+(https://docs.micropython.org/en/latest/develop/natmod.html).
+
+This should not be confused with [User C Modules]
+(https://docs.micropython.org/en/latest/develop/cmodules.html) which are a
+mechanism to add additional out-of-tree modules into the firmware build.
+
+## Examples
+
+This directory contains several examples of writing dynamic native modules, in
+two main categories:
+
+1.  Feature examples.
+
+    * `features0` - A module containing a single "factorial" function which
+      demonstrates working with integers.
+
+    * `features1` - A module that demonstrates some common tasks:
+        - defining simple functions exposed to Python
+        - defining local, helper C functions
+        - defining constant integers and strings exposed to Python
+        - getting and creating integer objects
+        - creating Python lists
+        - raising exceptions
+        - allocating memory
+        - BSS and constant data (rodata)
+        - relocated pointers in rodata
+
+    * `features2` - This is a hybrid module containing both Python and C code,
+      and additionally the C code is spread over multiple files. It also
+      demonstrates using floating point (only when the target supports
+      hardware floating point).
+
+    * `features3` - A module that shows how to use types, constant objects,
+      and creating dictionary instances.
+
+    * `features4` - A module that demonstrates how to define a class.
+
+2.  Dynamic version of existing built-ins.
+
+    This provides a way to add missing functionality to firmware that doesn't
+    include certain built-in modules. See the `heapq`, `random`, `re`,
+    `deflate`, `btree`, and `framebuf` directories.
+
+    So for example, if your firmware was compiled with `MICROPY_PY_FRAMEBUF`
+    disabled (e.g. to save flash space), then it would not include the
+    `framebuf` module. The `framebuf` native module provides a way to add the
+    `framebuf` module dynamically.
+
+    The way these work is they define a dynamic native module which
+    `#include`'s the original module and then does the necessary
+    initialisation of the module's globals dict.
+
+## Build instructions
+
+To compile an example, you need to have the same toolchain available as
+required for your target port. e.g. `arm-none-eabi-gcc` for any ARM Cortex M
+target. See the port instructions for details.
+
+You also need to have the `pyelftools` Python package available, either via
+your system package manager or installed from PyPI in a virtual environment
+with `pip`.
+
+Each example provides a Makefile. You should specify the `ARCH` argument to
+make (one of x86, x64, armv6m, armv7m, xtensa, xtensawin):
+
+```
+$ cd features0
+$ make ARCH=armv7m
+$ mpremote cp features0.mpy :
+```
diff --git a/examples/natmod/btree/btree_py.py b/examples/natmod/btree/btree_py.py
index bd53c084a1..461b045c98 100644
--- a/examples/natmod/btree/btree_py.py
+++ b/examples/natmod/btree/btree_py.py
@@ -1,3 +1,7 @@
 # Implemented in Python to support keyword arguments
+
+# ruff: noqa: F821 - this file is evaluated with C-defined names in scope
+
+
 def open(stream, *, flags=0, cachesize=0, pagesize=0, minkeypage=0):
     return _open(stream, flags, cachesize, pagesize, minkeypage)
diff --git a/examples/natmod/features2/test.py b/examples/natmod/features2/test.py
index 5ac80120d7..af79b9692c 100644
--- a/examples/natmod/features2/test.py
+++ b/examples/natmod/features2/test.py
@@ -1,5 +1,7 @@
 # This Python code will be merged with the C code in main.c
 
+# ruff: noqa: F821 - this file is evaluated with C-defined names in scope
+
 import array
 
 
diff --git a/examples/natmod/features4/Makefile b/examples/natmod/features4/Makefile
new file mode 100644
index 0000000000..f76a31a7cc
--- /dev/null
+++ b/examples/natmod/features4/Makefile
@@ -0,0 +1,14 @@
+# Location of top-level MicroPython directory
+MPY_DIR = ../../..
+
+# Name of module
+MOD = features4
+
+# Source files (.c or .py)
+SRC = features4.c
+
+# Architecture to build for (x86, x64, armv7m, xtensa, xtensawin)
+ARCH = x64
+
+# Include to get the rules for compiling and linking the module
+include $(MPY_DIR)/py/dynruntime.mk
diff --git a/examples/natmod/features4/features4.c b/examples/natmod/features4/features4.c
new file mode 100644
index 0000000000..336f4ecf64
--- /dev/null
+++ b/examples/natmod/features4/features4.c
@@ -0,0 +1,73 @@
+/*
+  This example extends on features0 but demonstrates how to define a class.
+
+  The Factorial class constructor takes an integer, and then the calculate
+  method can be called to get the factorial.
+
+  >>> import features4
+  >>> f = features4.Factorial(4)
+  >>> f.calculate()
+  24
+*/
+
+// Include the header file to get access to the MicroPython API
+#include "py/dynruntime.h"
+
+// This is type(Factorial)
+mp_obj_full_type_t mp_type_factorial;
+
+// This is the internal state of a Factorial instance.
+typedef struct {
+    mp_obj_base_t base;
+    mp_int_t n;
+} mp_obj_factorial_t;
+
+// Essentially Factorial.__new__ (but also kind of __init__).
+// Takes a single argument (the number to find the factorial of)
+STATIC mp_obj_t factorial_make_new(const mp_obj_type_t *type, size_t n_args, size_t n_kw, const mp_obj_t *args_in) {
+    mp_arg_check_num(n_args, n_kw, 1, 1, false);
+
+    mp_obj_factorial_t *o = mp_obj_malloc(mp_obj_factorial_t, type);
+    o->n = mp_obj_get_int(args_in[0]);
+
+    return MP_OBJ_FROM_PTR(o);
+}
+
+STATIC mp_int_t factorial_helper(mp_int_t x) {
+    if (x == 0) {
+        return 1;
+    }
+    return x * factorial_helper(x - 1);
+}
+
+// Implements Factorial.calculate()
+STATIC mp_obj_t factorial_calculate(mp_obj_t self_in) {
+    mp_obj_factorial_t *self = MP_OBJ_TO_PTR(self_in);
+    return mp_obj_new_int(factorial_helper(self->n));
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_1(factorial_calculate_obj, factorial_calculate);
+
+// Locals dict for the Factorial type (will have a single method, calculate,
+// added in mpy_init).
+mp_map_elem_t factorial_locals_dict_table[1];
+STATIC MP_DEFINE_CONST_DICT(factorial_locals_dict, factorial_locals_dict_table);
+
+// This is the entry point and is called when the module is imported
+mp_obj_t mpy_init(mp_obj_fun_bc_t *self, size_t n_args, size_t n_kw, mp_obj_t *args) {
+    // This must be first, it sets up the globals dict and other things
+    MP_DYNRUNTIME_INIT_ENTRY
+
+    // Initialise the type.
+    mp_type_factorial.base.type = (void*)&mp_type_type;
+    mp_type_factorial.flags = MP_TYPE_FLAG_NONE;
+    mp_type_factorial.name = MP_QSTR_Factorial;
+    MP_OBJ_TYPE_SET_SLOT(&mp_type_factorial, make_new, factorial_make_new, 0);
+    factorial_locals_dict_table[0] = (mp_map_elem_t){ MP_OBJ_NEW_QSTR(MP_QSTR_calculate), MP_OBJ_FROM_PTR(&factorial_calculate_obj) };
+    MP_OBJ_TYPE_SET_SLOT(&mp_type_factorial, locals_dict, (void*)&factorial_locals_dict, 1);
+
+    // Make the Factorial type available on the module.
+    mp_store_global(MP_QSTR_Factorial, MP_OBJ_FROM_PTR(&mp_type_factorial));
+
+    // This must be last, it restores the globals dict
+    MP_DYNRUNTIME_INIT_EXIT
+}
diff --git a/examples/rp2/pio_1hz.py b/examples/rp2/pio_1hz.py
index 84d761fa14..3ffab79d56 100644
--- a/examples/rp2/pio_1hz.py
+++ b/examples/rp2/pio_1hz.py
@@ -1,6 +1,8 @@
 # Example using PIO to blink an LED and raise an IRQ at 1Hz.
 # Note: this does not work on Pico W because it uses Pin(25) for LED output.
 
+# ruff: noqa: F821 - @asm_pio decorator adds names to function scope
+
 import time
 from machine import Pin
 import rp2
diff --git a/examples/rp2/pio_exec.py b/examples/rp2/pio_exec.py
index ce39f2df84..3bea51f8dd 100644
--- a/examples/rp2/pio_exec.py
+++ b/examples/rp2/pio_exec.py
@@ -5,6 +5,8 @@
 #   - using set_init and set_base
 #   - using StateMachine.exec
 
+# ruff: noqa: F821 - @asm_pio decorator adds names to function scope
+
 import time
 from machine import Pin
 import rp2
diff --git a/examples/rp2/pio_pinchange.py b/examples/rp2/pio_pinchange.py
index 767c8e78c2..4a210e7f39 100644
--- a/examples/rp2/pio_pinchange.py
+++ b/examples/rp2/pio_pinchange.py
@@ -8,6 +8,8 @@
 #   - setting an irq handler for a StateMachine
 #   - instantiating 2x StateMachine's with the same program and different pins
 
+# ruff: noqa: F821 - @asm_pio decorator adds names to function scope
+
 import time
 from machine import Pin
 import rp2
diff --git a/examples/rp2/pio_pwm.py b/examples/rp2/pio_pwm.py
index 176a238091..24fd6b85a3 100644
--- a/examples/rp2/pio_pwm.py
+++ b/examples/rp2/pio_pwm.py
@@ -1,5 +1,7 @@
 # Example of using PIO for PWM, and fading the brightness of an LED
 
+# ruff: noqa: F821 - @asm_pio decorator adds names to function scope
+
 from machine import Pin
 from rp2 import PIO, StateMachine, asm_pio
 from time import sleep
diff --git a/examples/rp2/pio_uart_rx.py b/examples/rp2/pio_uart_rx.py
index 080b6bd639..f46aaa6a5e 100644
--- a/examples/rp2/pio_uart_rx.py
+++ b/examples/rp2/pio_uart_rx.py
@@ -8,6 +8,8 @@
 #   - PIO irq handler
 #   - using the second core via _thread
 
+# ruff: noqa: F821 - @asm_pio decorator adds names to function scope
+
 import _thread
 from machine import Pin, UART
 from rp2 import PIO, StateMachine, asm_pio
diff --git a/examples/rp2/pio_uart_tx.py b/examples/rp2/pio_uart_tx.py
index 5e4af8f6cc..04abf2d0d1 100644
--- a/examples/rp2/pio_uart_tx.py
+++ b/examples/rp2/pio_uart_tx.py
@@ -1,5 +1,7 @@
 # Example using PIO to create a UART TX interface
 
+# ruff: noqa: F821 - @asm_pio decorator adds names to function scope
+
 from machine import Pin
 from rp2 import PIO, StateMachine, asm_pio
 
diff --git a/examples/rp2/pio_ws2812.py b/examples/rp2/pio_ws2812.py
index dd021a9d56..6de21ab8b7 100644
--- a/examples/rp2/pio_ws2812.py
+++ b/examples/rp2/pio_ws2812.py
@@ -1,5 +1,7 @@
 # Example using PIO to drive a set of WS2812 LEDs.
 
+# ruff: noqa: F821 - @asm_pio decorator adds names to function scope
+
 import array, time
 from machine import Pin
 import rp2
diff --git a/examples/rp2/pwm_fade.py b/examples/rp2/pwm_fade.py
index 5b7089c6b1..6672f3443f 100644
--- a/examples/rp2/pwm_fade.py
+++ b/examples/rp2/pwm_fade.py
@@ -1,6 +1,8 @@
 # Example using PWM to fade an LED.
 # Note: this does not work on Pico W because it uses Pin(25) for LED output.
 
+# ruff: noqa: F821 - @asm_pio decorator adds names to function scope
+
 import time
 from machine import Pin, PWM
 
diff --git a/extmod/extmod.cmake b/extmod/extmod.cmake
index 305cdee942..c8756a682e 100644
--- a/extmod/extmod.cmake
+++ b/extmod/extmod.cmake
@@ -60,51 +60,62 @@ set(MICROPY_SOURCE_EXTMOD
 
 if(MICROPY_PY_BTREE)
     set(MICROPY_LIB_BERKELEY_DIR "${MICROPY_DIR}/lib/berkeley-db-1.xx")
+    string(CONCAT GIT_SUBMODULES "${GIT_SUBMODULES} " lib/berkeley-db-1.xx)
 
-    add_library(micropy_extmod_btree OBJECT
-        ${MICROPY_LIB_BERKELEY_DIR}/btree/bt_close.c
-        ${MICROPY_LIB_BERKELEY_DIR}/btree/bt_conv.c
-        ${MICROPY_LIB_BERKELEY_DIR}/btree/bt_debug.c
-        ${MICROPY_LIB_BERKELEY_DIR}/btree/bt_delete.c
-        ${MICROPY_LIB_BERKELEY_DIR}/btree/bt_get.c
-        ${MICROPY_LIB_BERKELEY_DIR}/btree/bt_open.c
-        ${MICROPY_LIB_BERKELEY_DIR}/btree/bt_overflow.c
-        ${MICROPY_LIB_BERKELEY_DIR}/btree/bt_page.c
-        ${MICROPY_LIB_BERKELEY_DIR}/btree/bt_put.c
-        ${MICROPY_LIB_BERKELEY_DIR}/btree/bt_search.c
-        ${MICROPY_LIB_BERKELEY_DIR}/btree/bt_seq.c
-        ${MICROPY_LIB_BERKELEY_DIR}/btree/bt_split.c
-        ${MICROPY_LIB_BERKELEY_DIR}/btree/bt_utils.c
-        ${MICROPY_LIB_BERKELEY_DIR}/mpool/mpool.c
-    )
+    if(ECHO_SUBMODULES)
+        # No-op, we're just doing submodule/variant discovery.
+        # Cannot run the add_library/target_include_directories rules (even though
+        # the build won't run) because IDF will attempt verify the files exist.
+    elseif(NOT EXISTS ${MICROPY_LIB_BERKELEY_DIR}/README)
+        # Regular build, submodule not initialised -- fail with a clear error.
+        message(FATAL_ERROR " MICROPY_PY_BTREE is enabled but the berkeley-db submodule is not initialised.\n Run 'make BOARD=${MICROPY_BOARD} submodules'")
+    else()
+        # Regular build, we have the submodule.
+        add_library(micropy_extmod_btree OBJECT
+            ${MICROPY_LIB_BERKELEY_DIR}/btree/bt_close.c
+            ${MICROPY_LIB_BERKELEY_DIR}/btree/bt_conv.c
+            ${MICROPY_LIB_BERKELEY_DIR}/btree/bt_debug.c
+            ${MICROPY_LIB_BERKELEY_DIR}/btree/bt_delete.c
+            ${MICROPY_LIB_BERKELEY_DIR}/btree/bt_get.c
+            ${MICROPY_LIB_BERKELEY_DIR}/btree/bt_open.c
+            ${MICROPY_LIB_BERKELEY_DIR}/btree/bt_overflow.c
+            ${MICROPY_LIB_BERKELEY_DIR}/btree/bt_page.c
+            ${MICROPY_LIB_BERKELEY_DIR}/btree/bt_put.c
+            ${MICROPY_LIB_BERKELEY_DIR}/btree/bt_search.c
+            ${MICROPY_LIB_BERKELEY_DIR}/btree/bt_seq.c
+            ${MICROPY_LIB_BERKELEY_DIR}/btree/bt_split.c
+            ${MICROPY_LIB_BERKELEY_DIR}/btree/bt_utils.c
+            ${MICROPY_LIB_BERKELEY_DIR}/mpool/mpool.c
+        )
 
-    target_include_directories(micropy_extmod_btree PRIVATE
-        ${MICROPY_LIB_BERKELEY_DIR}/PORT/include
-    )
+        target_include_directories(micropy_extmod_btree PRIVATE
+            ${MICROPY_LIB_BERKELEY_DIR}/PORT/include
+        )
 
-    target_compile_definitions(micropy_extmod_btree PRIVATE
-        __DBINTERFACE_PRIVATE=1
-        mpool_error=printf
-        abort=abort_
-        "virt_fd_t=void*"
-    )
+        target_compile_definitions(micropy_extmod_btree PRIVATE
+            __DBINTERFACE_PRIVATE=1
+            mpool_error=printf
+            abort=abort_
+            "virt_fd_t=void*"
+        )
 
-    # The include directories and compile definitions below are needed to build
-    # modbtree.c and should be added to the main MicroPython target.
+        # The include directories and compile definitions below are needed to build
+        # modbtree.c and should be added to the main MicroPython target.
 
-    list(APPEND MICROPY_INC_CORE
-        "${MICROPY_LIB_BERKELEY_DIR}/PORT/include"
-    )
+        list(APPEND MICROPY_INC_CORE
+            "${MICROPY_LIB_BERKELEY_DIR}/PORT/include"
+        )
 
-    list(APPEND MICROPY_DEF_CORE
-        MICROPY_PY_BTREE=1
-        __DBINTERFACE_PRIVATE=1
-        "virt_fd_t=void*"
-    )
+        list(APPEND MICROPY_DEF_CORE
+            MICROPY_PY_BTREE=1
+            __DBINTERFACE_PRIVATE=1
+            "virt_fd_t=void*"
+        )
 
-    list(APPEND MICROPY_SOURCE_EXTMOD
-        ${MICROPY_EXTMOD_DIR}/modbtree.c
-    )
+        list(APPEND MICROPY_SOURCE_EXTMOD
+            ${MICROPY_EXTMOD_DIR}/modbtree.c
+        )
+    endif()
 endif()
 
 # Library for mbedtls
diff --git a/extmod/moddeflate.c b/extmod/moddeflate.c
index 1d8a8acf73..560ee3f0ab 100644
--- a/extmod/moddeflate.c
+++ b/extmod/moddeflate.c
@@ -54,6 +54,8 @@ typedef enum {
     DEFLATEIO_FORMAT_MAX = DEFLATEIO_FORMAT_GZIP,
 } deflateio_format_t;
 
+// This is used when the wbits is unset in the DeflateIO constructor. Default
+// to the smallest window size (faster compression, less RAM usage, etc).
 const int DEFLATEIO_DEFAULT_WBITS = 8;
 
 typedef struct {
@@ -114,24 +116,32 @@ STATIC bool deflateio_init_read(mp_obj_deflateio_t *self) {
     // Don't modify self->window_bits as it may also be used for write.
     int wbits = self->window_bits;
 
-    // Parse the header if we're in NONE/ZLIB/GZIP modes.
-    if (self->format != DEFLATEIO_FORMAT_RAW) {
-        int header_wbits = wbits;
+    if (self->format == DEFLATEIO_FORMAT_RAW) {
+        if (wbits == 0) {
+            // The docs recommends always setting wbits explicitly when using
+            // RAW, but we still allow a default.
+            wbits = DEFLATEIO_DEFAULT_WBITS;
+        }
+    } else {
+        // Parse the header if we're in NONE/ZLIB/GZIP modes.
+        int header_wbits;
         int header_type = uzlib_parse_zlib_gzip_header(&self->read->decomp, &header_wbits);
-        if ((self->format == DEFLATEIO_FORMAT_ZLIB && header_type != UZLIB_HEADER_ZLIB) || (self->format == DEFLATEIO_FORMAT_GZIP && header_type != UZLIB_HEADER_GZIP)) {
+        if (header_type < 0) {
+            // Stream header was invalid.
             return false;
         }
-        if (wbits == 0 && header_wbits < 15) {
-            // If the header specified something lower than the default, then
-            // use that instead.
+        if ((self->format == DEFLATEIO_FORMAT_ZLIB && header_type != UZLIB_HEADER_ZLIB) || (self->format == DEFLATEIO_FORMAT_GZIP && header_type != UZLIB_HEADER_GZIP)) {
+            // Not what we expected.
+            return false;
+        }
+        // header_wbits will either be 15 (gzip) or 8-15 (zlib).
+        if (wbits == 0 || header_wbits < wbits) {
+            // If the header specified something lower, then use that instead.
+            // No point doing a bigger allocation than we need to.
             wbits = header_wbits;
         }
     }
 
-    if (wbits == 0) {
-        wbits = DEFLATEIO_DEFAULT_WBITS;
-    }
-
     size_t window_len = 1 << wbits;
     self->read->window = m_new(uint8_t, window_len);
 
@@ -163,6 +173,7 @@ STATIC bool deflateio_init_write(mp_obj_deflateio_t *self) {
 
     int wbits = self->window_bits;
     if (wbits == 0) {
+        // Same default wbits for all formats.
         wbits = DEFLATEIO_DEFAULT_WBITS;
     }
     size_t window_len = 1 << wbits;
diff --git a/extmod/modlwip.c b/extmod/modlwip.c
index 0d4c03c68a..c881f0df6a 100644
--- a/extmod/modlwip.c
+++ b/extmod/modlwip.c
@@ -1377,7 +1377,8 @@ STATIC mp_obj_t lwip_socket_setsockopt(size_t n_args, const mp_obj_t *args) {
 
     switch (opt) {
         // level: SOL_SOCKET
-        case SOF_REUSEADDR: {
+        case SOF_REUSEADDR:
+        case SOF_BROADCAST: {
             mp_int_t val = mp_obj_get_int(args[3]);
             // Options are common for UDP and TCP pcb's.
             if (val) {
@@ -1786,6 +1787,7 @@ STATIC const mp_rom_map_elem_t mp_module_lwip_globals_table[] = {
 
     { MP_ROM_QSTR(MP_QSTR_SOL_SOCKET), MP_ROM_INT(1) },
     { MP_ROM_QSTR(MP_QSTR_SO_REUSEADDR), MP_ROM_INT(SOF_REUSEADDR) },
+    { MP_ROM_QSTR(MP_QSTR_SO_BROADCAST), MP_ROM_INT(SOF_BROADCAST) },
 
     { MP_ROM_QSTR(MP_QSTR_IPPROTO_IP), MP_ROM_INT(0) },
     { MP_ROM_QSTR(MP_QSTR_IP_ADD_MEMBERSHIP), MP_ROM_INT(IP_ADD_MEMBERSHIP) },
diff --git a/extmod/modnetwork.h b/extmod/modnetwork.h
index 4786596e9b..e775612fe7 100644
--- a/extmod/modnetwork.h
+++ b/extmod/modnetwork.h
@@ -43,6 +43,7 @@
 
 // Common option flags per-socket.
 #define MOD_NETWORK_SO_REUSEADDR    (0x0004)
+#define MOD_NETWORK_SO_BROADCAST    (0x0020)
 #define MOD_NETWORK_SO_KEEPALIVE    (0x0008)
 #define MOD_NETWORK_SO_SNDTIMEO     (0x1005)
 #define MOD_NETWORK_SO_RCVTIMEO     (0x1006)
diff --git a/extmod/modselect.c b/extmod/modselect.c
index 3d7ccbd995..d665a10827 100644
--- a/extmod/modselect.c
+++ b/extmod/modselect.c
@@ -3,7 +3,7 @@
  *
  * The MIT License (MIT)
  *
- * Copyright (c) 2014 Damien P. George
+ * Copyright (c) 2014-2023 Damien P. George
  * Copyright (c) 2015-2017 Paul Sokolovsky
  *
  * Permission is hereby granted, free of charge, to any person obtaining a copy
@@ -26,10 +26,6 @@
  */
 
 #include "py/mpconfig.h"
-#if MICROPY_PY_SELECT
-
-#include <stdio.h>
-
 #include "py/runtime.h"
 #include "py/obj.h"
 #include "py/objlist.h"
@@ -37,51 +33,248 @@
 #include "py/mperrno.h"
 #include "py/mphal.h"
 
-// Flags for poll()
+#if MICROPY_PY_SELECT
+
+#if MICROPY_PY_SELECT_SELECT && MICROPY_PY_SELECT_POSIX_OPTIMISATIONS
+#error "select.select is not supported with MICROPY_PY_SELECT_POSIX_OPTIMISATIONS"
+#endif
+
+#if MICROPY_PY_SELECT_POSIX_OPTIMISATIONS
+
+#include <poll.h>
+
+#if !((MP_STREAM_POLL_RD) == (POLLIN) && \
+    (MP_STREAM_POLL_WR) == (POLLOUT) && \
+    (MP_STREAM_POLL_ERR) == (POLLERR) && \
+    (MP_STREAM_POLL_HUP) == (POLLHUP) && \
+    (MP_STREAM_POLL_NVAL) == (POLLNVAL))
+#error "With MICROPY_PY_SELECT_POSIX_OPTIMISATIONS enabled, POLL constants must match"
+#endif
+
+// When non-file-descriptor objects are on the list to be polled (the polling of
+// which involves repeatedly calling ioctl(MP_STREAM_POLL)), this variable sets
+// the period between polling these objects.
+#define MICROPY_PY_SELECT_IOCTL_CALL_PERIOD_MS (1)
+
+#endif
+
+// Flags for ipoll()
 #define FLAG_ONESHOT (1)
 
+// A single pollable object.
 typedef struct _poll_obj_t {
     mp_obj_t obj;
     mp_uint_t (*ioctl)(mp_obj_t obj, mp_uint_t request, uintptr_t arg, int *errcode);
-    mp_uint_t flags;
-    mp_uint_t flags_ret;
+    #if MICROPY_PY_SELECT_POSIX_OPTIMISATIONS
+    // If the pollable object has an associated file descriptor, then pollfd points to an entry
+    // in poll_set_t::pollfds, and the events/revents fields for this object are stored in the
+    // pollfd entry (and the nonfd_* members are unused).
+    // Otherwise the object is a non-file-descriptor object and pollfd==NULL, and the events/
+    // revents fields are stored in the nonfd_* members (which are named as such so that code
+    // doesn't accidentally mix the use of these members when this optimisation is used).
+    struct pollfd *pollfd;
+    uint16_t nonfd_events;
+    uint16_t nonfd_revents;
+    #else
+    mp_uint_t events;
+    mp_uint_t revents;
+    #endif
 } poll_obj_t;
 
-STATIC void poll_map_add(mp_map_t *poll_map, const mp_obj_t *obj, mp_uint_t obj_len, mp_uint_t flags, bool or_flags) {
+// A set of pollable objects.
+typedef struct _poll_set_t {
+    // Map containing a dict with key=object to poll, value=its corresponding poll_obj_t.
+    mp_map_t map;
+
+    #if MICROPY_PY_SELECT_POSIX_OPTIMISATIONS
+    // Array of pollfd entries for objects that have a file descriptor.
+    unsigned short alloc; // memory allocated for pollfds
+    unsigned short max_used; // maximum number of used entries in pollfds
+    unsigned short used; // actual number of used entries in pollfds
+    struct pollfd *pollfds;
+    #endif
+} poll_set_t;
+
+STATIC void poll_set_init(poll_set_t *poll_set, size_t n) {
+    mp_map_init(&poll_set->map, n);
+    #if MICROPY_PY_SELECT_POSIX_OPTIMISATIONS
+    poll_set->alloc = 0;
+    poll_set->max_used = 0;
+    poll_set->used = 0;
+    poll_set->pollfds = NULL;
+    #endif
+}
+
+#if MICROPY_PY_SELECT_SELECT
+STATIC void poll_set_deinit(poll_set_t *poll_set) {
+    mp_map_deinit(&poll_set->map);
+}
+#endif
+
+#if MICROPY_PY_SELECT_POSIX_OPTIMISATIONS
+
+STATIC mp_uint_t poll_obj_get_events(poll_obj_t *poll_obj) {
+    assert(poll_obj->pollfd == NULL);
+    return poll_obj->nonfd_events;
+}
+
+STATIC void poll_obj_set_events(poll_obj_t *poll_obj, mp_uint_t events) {
+    if (poll_obj->pollfd != NULL) {
+        poll_obj->pollfd->events = events;
+    } else {
+        poll_obj->nonfd_events = events;
+    }
+}
+
+STATIC mp_uint_t poll_obj_get_revents(poll_obj_t *poll_obj) {
+    if (poll_obj->pollfd != NULL) {
+        return poll_obj->pollfd->revents;
+    } else {
+        return poll_obj->nonfd_revents;
+    }
+}
+
+STATIC void poll_obj_set_revents(poll_obj_t *poll_obj, mp_uint_t revents) {
+    if (poll_obj->pollfd != NULL) {
+        poll_obj->pollfd->revents = revents;
+    } else {
+        poll_obj->nonfd_revents = revents;
+    }
+}
+
+STATIC struct pollfd *poll_set_add_fd(poll_set_t *poll_set, int fd) {
+    struct pollfd *free_slot = NULL;
+
+    if (poll_set->used == poll_set->max_used) {
+        // No free slots below max_used, so expand max_used (and possibly allocate).
+        if (poll_set->max_used >= poll_set->alloc) {
+            poll_set->pollfds = m_renew(struct pollfd, poll_set->pollfds, poll_set->alloc, poll_set->alloc + 4);
+            poll_set->alloc += 4;
+        }
+        free_slot = &poll_set->pollfds[poll_set->max_used++];
+    } else {
+        // There should be a free slot below max_used.
+        for (unsigned int i = 0; i < poll_set->max_used; ++i) {
+            struct pollfd *slot = &poll_set->pollfds[i];
+            if (slot->fd == -1) {
+                free_slot = slot;
+                break;
+            }
+        }
+        assert(free_slot != NULL);
+    }
+
+    free_slot->fd = fd;
+    ++poll_set->used;
+
+    return free_slot;
+}
+
+static inline bool poll_set_all_are_fds(poll_set_t *poll_set) {
+    return poll_set->map.used == poll_set->used;
+}
+
+#else
+
+static inline mp_uint_t poll_obj_get_events(poll_obj_t *poll_obj) {
+    return poll_obj->events;
+}
+
+static inline void poll_obj_set_events(poll_obj_t *poll_obj, mp_uint_t events) {
+    poll_obj->events = events;
+}
+
+static inline mp_uint_t poll_obj_get_revents(poll_obj_t *poll_obj) {
+    return poll_obj->revents;
+}
+
+static inline void poll_obj_set_revents(poll_obj_t *poll_obj, mp_uint_t revents) {
+    poll_obj->revents = revents;
+}
+
+#endif
+
+STATIC void poll_set_add_obj(poll_set_t *poll_set, const mp_obj_t *obj, mp_uint_t obj_len, mp_uint_t events, bool or_events) {
     for (mp_uint_t i = 0; i < obj_len; i++) {
-        mp_map_elem_t *elem = mp_map_lookup(poll_map, mp_obj_id(obj[i]), MP_MAP_LOOKUP_ADD_IF_NOT_FOUND);
+        mp_map_elem_t *elem = mp_map_lookup(&poll_set->map, mp_obj_id(obj[i]), MP_MAP_LOOKUP_ADD_IF_NOT_FOUND);
         if (elem->value == MP_OBJ_NULL) {
             // object not found; get its ioctl and add it to the poll list
-            const mp_stream_p_t *stream_p = mp_get_stream_raise(obj[i], MP_STREAM_OP_IOCTL);
+
+            // If an exception is raised below when adding the new object then the map entry for that
+            // object remains unpopulated, and methods like poll() may crash.  This case is not handled.
+
             poll_obj_t *poll_obj = m_new_obj(poll_obj_t);
             poll_obj->obj = obj[i];
+
+            #if MICROPY_PY_SELECT_POSIX_OPTIMISATIONS
+            int fd = -1;
+            if (mp_obj_is_int(obj[i])) {
+                // A file descriptor integer passed in as the object, so use it directly.
+                fd = mp_obj_get_int(obj[i]);
+                if (fd < 0) {
+                    mp_raise_ValueError(NULL);
+                }
+                poll_obj->ioctl = NULL;
+            } else {
+                // An object passed in.  Check if it has a file descriptor.
+                const mp_stream_p_t *stream_p = mp_get_stream_raise(obj[i], MP_STREAM_OP_IOCTL);
+                poll_obj->ioctl = stream_p->ioctl;
+                int err;
+                mp_uint_t res = stream_p->ioctl(obj[i], MP_STREAM_GET_FILENO, 0, &err);
+                if (res != MP_STREAM_ERROR) {
+                    fd = res;
+                }
+            }
+            if (fd >= 0) {
+                // Object has a file descriptor so add it to pollfds.
+                poll_obj->pollfd = poll_set_add_fd(poll_set, fd);
+            } else {
+                // Object doesn't have a file descriptor.
+                poll_obj->pollfd = NULL;
+            }
+            #else
+            const mp_stream_p_t *stream_p = mp_get_stream_raise(obj[i], MP_STREAM_OP_IOCTL);
             poll_obj->ioctl = stream_p->ioctl;
-            poll_obj->flags = flags;
-            poll_obj->flags_ret = 0;
+            #endif
+
+            poll_obj_set_events(poll_obj, events);
+            poll_obj_set_revents(poll_obj, 0);
             elem->value = MP_OBJ_FROM_PTR(poll_obj);
         } else {
-            // object exists; update its flags
-            if (or_flags) {
-                ((poll_obj_t *)MP_OBJ_TO_PTR(elem->value))->flags |= flags;
-            } else {
-                ((poll_obj_t *)MP_OBJ_TO_PTR(elem->value))->flags = flags;
+            // object exists; update its events
+            poll_obj_t *poll_obj = (poll_obj_t *)MP_OBJ_TO_PTR(elem->value);
+            #if MICROPY_PY_SELECT_SELECT
+            if (or_events) {
+                events |= poll_obj_get_events(poll_obj);
             }
+            #else
+            (void)or_events;
+            #endif
+            poll_obj_set_events(poll_obj, events);
         }
     }
 }
 
-// poll each object in the map
-STATIC mp_uint_t poll_map_poll(mp_map_t *poll_map, size_t *rwx_num) {
+// For each object in the poll set, poll it once.
+STATIC mp_uint_t poll_set_poll_once(poll_set_t *poll_set, size_t *rwx_num) {
     mp_uint_t n_ready = 0;
-    for (mp_uint_t i = 0; i < poll_map->alloc; ++i) {
-        if (!mp_map_slot_is_filled(poll_map, i)) {
+    for (mp_uint_t i = 0; i < poll_set->map.alloc; ++i) {
+        if (!mp_map_slot_is_filled(&poll_set->map, i)) {
             continue;
         }
 
-        poll_obj_t *poll_obj = MP_OBJ_TO_PTR(poll_map->table[i].value);
+        poll_obj_t *poll_obj = MP_OBJ_TO_PTR(poll_set->map.table[i].value);
+
+        #if MICROPY_PY_SELECT_POSIX_OPTIMISATIONS
+        if (poll_obj->pollfd != NULL) {
+            // Object has file descriptor so will be polled separately by poll().
+            continue;
+        }
+        #endif
+
         int errcode;
-        mp_int_t ret = poll_obj->ioctl(poll_obj->obj, MP_STREAM_POLL, poll_obj->flags, &errcode);
-        poll_obj->flags_ret = ret;
+        mp_int_t ret = poll_obj->ioctl(poll_obj->obj, MP_STREAM_POLL, poll_obj_get_events(poll_obj), &errcode);
+        poll_obj_set_revents(poll_obj, ret);
 
         if (ret == -1) {
             // error doing ioctl
@@ -91,6 +284,7 @@ STATIC mp_uint_t poll_map_poll(mp_map_t *poll_map, size_t *rwx_num) {
         if (ret != 0) {
             // object is ready
             n_ready += 1;
+            #if MICROPY_PY_SELECT_SELECT
             if (rwx_num != NULL) {
                 if (ret & MP_STREAM_POLL_RD) {
                     rwx_num[0] += 1;
@@ -102,11 +296,82 @@ STATIC mp_uint_t poll_map_poll(mp_map_t *poll_map, size_t *rwx_num) {
                     rwx_num[2] += 1;
                 }
             }
+            #else
+            (void)rwx_num;
+            #endif
         }
     }
     return n_ready;
 }
 
+STATIC mp_uint_t poll_set_poll_until_ready_or_timeout(poll_set_t *poll_set, size_t *rwx_num, mp_uint_t timeout) {
+    mp_uint_t start_ticks = mp_hal_ticks_ms();
+
+    #if MICROPY_PY_SELECT_POSIX_OPTIMISATIONS
+
+    for (;;) {
+        MP_THREAD_GIL_EXIT();
+
+        // Compute the timeout.
+        int t = MICROPY_PY_SELECT_IOCTL_CALL_PERIOD_MS;
+        if (poll_set_all_are_fds(poll_set)) {
+            // All our pollables are file descriptors, so we can use a blocking
+            // poll and let it (the underlying system) handle the timeout.
+            if (timeout == (mp_uint_t)-1) {
+                t = -1;
+            } else {
+                mp_uint_t delta = mp_hal_ticks_ms() - start_ticks;
+                if (delta >= timeout) {
+                    t = 0;
+                } else {
+                    t = timeout - delta;
+                }
+            }
+        }
+
+        // Call system poll for those objects that have a file descriptor.
+        int n_ready = poll(poll_set->pollfds, poll_set->max_used, t);
+
+        MP_THREAD_GIL_ENTER();
+
+        // The call to poll() may have been interrupted, but per PEP 475 we must retry if the
+        // signal is EINTR (this implements a special case of calling MP_HAL_RETRY_SYSCALL()).
+        if (n_ready == -1) {
+            int err = errno;
+            if (err != EINTR) {
+                mp_raise_OSError(err);
+            }
+            n_ready = 0;
+        }
+
+        // Explicitly poll any objects that do not have a file descriptor.
+        if (!poll_set_all_are_fds(poll_set)) {
+            n_ready += poll_set_poll_once(poll_set, rwx_num);
+        }
+
+        // Return if an object is ready, or if the timeout expired.
+        if (n_ready > 0 || (timeout != (mp_uint_t)-1 && mp_hal_ticks_ms() - start_ticks >= timeout)) {
+            return n_ready;
+        }
+
+        // This would be MICROPY_EVENT_POLL_HOOK but the call to poll() above already includes a delay.
+        mp_handle_pending(true);
+    }
+
+    #else
+
+    for (;;) {
+        // poll the objects
+        mp_uint_t n_ready = poll_set_poll_once(poll_set, rwx_num);
+        if (n_ready > 0 || (timeout != (mp_uint_t)-1 && mp_hal_ticks_ms() - start_ticks >= timeout)) {
+            return n_ready;
+        }
+        MICROPY_EVENT_POLL_HOOK
+    }
+
+    #endif
+}
+
 #if MICROPY_PY_SELECT_SELECT
 // select(rlist, wlist, xlist[, timeout])
 STATIC mp_obj_t select_select(size_t n_args, const mp_obj_t *args) {
@@ -133,52 +398,46 @@ STATIC mp_obj_t select_select(size_t n_args, const mp_obj_t *args) {
     }
 
     // merge separate lists and get the ioctl function for each object
-    mp_map_t poll_map;
-    mp_map_init(&poll_map, rwx_len[0] + rwx_len[1] + rwx_len[2]);
-    poll_map_add(&poll_map, r_array, rwx_len[0], MP_STREAM_POLL_RD, true);
-    poll_map_add(&poll_map, w_array, rwx_len[1], MP_STREAM_POLL_WR, true);
-    poll_map_add(&poll_map, x_array, rwx_len[2], MP_STREAM_POLL_ERR | MP_STREAM_POLL_HUP, true);
+    poll_set_t poll_set;
+    poll_set_init(&poll_set, rwx_len[0] + rwx_len[1] + rwx_len[2]);
+    poll_set_add_obj(&poll_set, r_array, rwx_len[0], MP_STREAM_POLL_RD, true);
+    poll_set_add_obj(&poll_set, w_array, rwx_len[1], MP_STREAM_POLL_WR, true);
+    poll_set_add_obj(&poll_set, x_array, rwx_len[2], MP_STREAM_POLL_ERR | MP_STREAM_POLL_HUP, true);
 
-    mp_uint_t start_tick = mp_hal_ticks_ms();
+    // poll all objects
     rwx_len[0] = rwx_len[1] = rwx_len[2] = 0;
-    for (;;) {
-        // poll the objects
-        mp_uint_t n_ready = poll_map_poll(&poll_map, rwx_len);
+    poll_set_poll_until_ready_or_timeout(&poll_set, rwx_len, timeout);
 
-        if (n_ready > 0 || (timeout != (mp_uint_t)-1 && mp_hal_ticks_ms() - start_tick >= timeout)) {
-            // one or more objects are ready, or we had a timeout
-            mp_obj_t list_array[3];
-            list_array[0] = mp_obj_new_list(rwx_len[0], NULL);
-            list_array[1] = mp_obj_new_list(rwx_len[1], NULL);
-            list_array[2] = mp_obj_new_list(rwx_len[2], NULL);
-            rwx_len[0] = rwx_len[1] = rwx_len[2] = 0;
-            for (mp_uint_t i = 0; i < poll_map.alloc; ++i) {
-                if (!mp_map_slot_is_filled(&poll_map, i)) {
-                    continue;
-                }
-                poll_obj_t *poll_obj = MP_OBJ_TO_PTR(poll_map.table[i].value);
-                if (poll_obj->flags_ret & MP_STREAM_POLL_RD) {
-                    ((mp_obj_list_t *)MP_OBJ_TO_PTR(list_array[0]))->items[rwx_len[0]++] = poll_obj->obj;
-                }
-                if (poll_obj->flags_ret & MP_STREAM_POLL_WR) {
-                    ((mp_obj_list_t *)MP_OBJ_TO_PTR(list_array[1]))->items[rwx_len[1]++] = poll_obj->obj;
-                }
-                if ((poll_obj->flags_ret & ~(MP_STREAM_POLL_RD | MP_STREAM_POLL_WR)) != 0) {
-                    ((mp_obj_list_t *)MP_OBJ_TO_PTR(list_array[2]))->items[rwx_len[2]++] = poll_obj->obj;
-                }
-            }
-            mp_map_deinit(&poll_map);
-            return mp_obj_new_tuple(3, list_array);
+    // one or more objects are ready, or we had a timeout
+    mp_obj_t list_array[3];
+    list_array[0] = mp_obj_new_list(rwx_len[0], NULL);
+    list_array[1] = mp_obj_new_list(rwx_len[1], NULL);
+    list_array[2] = mp_obj_new_list(rwx_len[2], NULL);
+    rwx_len[0] = rwx_len[1] = rwx_len[2] = 0;
+    for (mp_uint_t i = 0; i < poll_set.map.alloc; ++i) {
+        if (!mp_map_slot_is_filled(&poll_set.map, i)) {
+            continue;
+        }
+        poll_obj_t *poll_obj = MP_OBJ_TO_PTR(poll_set.map.table[i].value);
+        if (poll_obj->revents & MP_STREAM_POLL_RD) {
+            ((mp_obj_list_t *)MP_OBJ_TO_PTR(list_array[0]))->items[rwx_len[0]++] = poll_obj->obj;
+        }
+        if (poll_obj->revents & MP_STREAM_POLL_WR) {
+            ((mp_obj_list_t *)MP_OBJ_TO_PTR(list_array[1]))->items[rwx_len[1]++] = poll_obj->obj;
+        }
+        if ((poll_obj->revents & ~(MP_STREAM_POLL_RD | MP_STREAM_POLL_WR)) != 0) {
+            ((mp_obj_list_t *)MP_OBJ_TO_PTR(list_array[2]))->items[rwx_len[2]++] = poll_obj->obj;
         }
-        MICROPY_EVENT_POLL_HOOK
     }
+    poll_set_deinit(&poll_set);
+    return mp_obj_new_tuple(3, list_array);
 }
 MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(mp_select_select_obj, 3, 4, select_select);
 #endif // MICROPY_PY_SELECT_SELECT
 
 typedef struct _mp_obj_poll_t {
     mp_obj_base_t base;
-    mp_map_t poll_map;
+    poll_set_t poll_set;
     short iter_cnt;
     short iter_idx;
     int flags;
@@ -189,13 +448,13 @@ typedef struct _mp_obj_poll_t {
 // register(obj[, eventmask])
 STATIC mp_obj_t poll_register(size_t n_args, const mp_obj_t *args) {
     mp_obj_poll_t *self = MP_OBJ_TO_PTR(args[0]);
-    mp_uint_t flags;
+    mp_uint_t events;
     if (n_args == 3) {
-        flags = mp_obj_get_int(args[2]);
+        events = mp_obj_get_int(args[2]);
     } else {
-        flags = MP_STREAM_POLL_RD | MP_STREAM_POLL_WR;
+        events = MP_STREAM_POLL_RD | MP_STREAM_POLL_WR;
     }
-    poll_map_add(&self->poll_map, &args[1], 1, flags, false);
+    poll_set_add_obj(&self->poll_set, &args[1], 1, events, false);
     return mp_const_none;
 }
 MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(poll_register_obj, 2, 3, poll_register);
@@ -203,7 +462,21 @@ MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(poll_register_obj, 2, 3, poll_register);
 // unregister(obj)
 STATIC mp_obj_t poll_unregister(mp_obj_t self_in, mp_obj_t obj_in) {
     mp_obj_poll_t *self = MP_OBJ_TO_PTR(self_in);
-    mp_map_lookup(&self->poll_map, mp_obj_id(obj_in), MP_MAP_LOOKUP_REMOVE_IF_FOUND);
+    mp_map_elem_t *elem = mp_map_lookup(&self->poll_set.map, mp_obj_id(obj_in), MP_MAP_LOOKUP_REMOVE_IF_FOUND);
+
+    #if MICROPY_PY_SELECT_POSIX_OPTIMISATIONS
+    if (elem != NULL) {
+        poll_obj_t *poll_obj = (poll_obj_t *)MP_OBJ_TO_PTR(elem->value);
+        if (poll_obj->pollfd != NULL) {
+            poll_obj->pollfd->fd = -1;
+            --self->poll_set.used;
+        }
+        elem->value = MP_OBJ_NULL;
+    }
+    #else
+    (void)elem;
+    #endif
+
     // TODO raise KeyError if obj didn't exist in map
     return mp_const_none;
 }
@@ -212,11 +485,11 @@ MP_DEFINE_CONST_FUN_OBJ_2(poll_unregister_obj, poll_unregister);
 // modify(obj, eventmask)
 STATIC mp_obj_t poll_modify(mp_obj_t self_in, mp_obj_t obj_in, mp_obj_t eventmask_in) {
     mp_obj_poll_t *self = MP_OBJ_TO_PTR(self_in);
-    mp_map_elem_t *elem = mp_map_lookup(&self->poll_map, mp_obj_id(obj_in), MP_MAP_LOOKUP);
+    mp_map_elem_t *elem = mp_map_lookup(&self->poll_set.map, mp_obj_id(obj_in), MP_MAP_LOOKUP);
     if (elem == NULL) {
         mp_raise_OSError(MP_ENOENT);
     }
-    ((poll_obj_t *)MP_OBJ_TO_PTR(elem->value))->flags = mp_obj_get_int(eventmask_in);
+    poll_obj_set_events((poll_obj_t *)MP_OBJ_TO_PTR(elem->value), mp_obj_get_int(eventmask_in));
     return mp_const_none;
 }
 MP_DEFINE_CONST_FUN_OBJ_3(poll_modify_obj, poll_modify);
@@ -241,18 +514,7 @@ STATIC mp_uint_t poll_poll_internal(uint n_args, const mp_obj_t *args) {
 
     self->flags = flags;
 
-    mp_uint_t start_tick = mp_hal_ticks_ms();
-    mp_uint_t n_ready;
-    for (;;) {
-        // poll the objects
-        n_ready = poll_map_poll(&self->poll_map, NULL);
-        if (n_ready > 0 || (timeout != (mp_uint_t)-1 && mp_hal_ticks_ms() - start_tick >= timeout)) {
-            break;
-        }
-        MICROPY_EVENT_POLL_HOOK
-    }
-
-    return n_ready;
+    return poll_set_poll_until_ready_or_timeout(&self->poll_set, NULL, timeout);
 }
 
 STATIC mp_obj_t poll_poll(size_t n_args, const mp_obj_t *args) {
@@ -262,23 +524,19 @@ STATIC mp_obj_t poll_poll(size_t n_args, const mp_obj_t *args) {
     // one or more objects are ready, or we had a timeout
     mp_obj_list_t *ret_list = MP_OBJ_TO_PTR(mp_obj_new_list(n_ready, NULL));
     n_ready = 0;
-    for (mp_uint_t i = 0; i < self->poll_map.alloc; ++i) {
-        if (!mp_map_slot_is_filled(&self->poll_map, i)) {
+    for (mp_uint_t i = 0; i < self->poll_set.map.alloc; ++i) {
+        if (!mp_map_slot_is_filled(&self->poll_set.map, i)) {
             continue;
         }
-        poll_obj_t *poll_obj = MP_OBJ_TO_PTR(self->poll_map.table[i].value);
-        if (poll_obj->flags_ret != 0) {
-            mp_obj_t tuple[2] = {poll_obj->obj, MP_OBJ_NEW_SMALL_INT(poll_obj->flags_ret)};
+        poll_obj_t *poll_obj = MP_OBJ_TO_PTR(self->poll_set.map.table[i].value);
+        if (poll_obj_get_revents(poll_obj) != 0) {
+            mp_obj_t tuple[2] = {poll_obj->obj, MP_OBJ_NEW_SMALL_INT(poll_obj_get_revents(poll_obj))};
             ret_list->items[n_ready++] = mp_obj_new_tuple(2, tuple);
-            if (self->flags & FLAG_ONESHOT) {
-                // Don't poll next time, until new event flags will be set explicitly
-                poll_obj->flags = 0;
-            }
         }
     }
     return MP_OBJ_FROM_PTR(ret_list);
 }
-MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(poll_poll_obj, 1, 3, poll_poll);
+MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(poll_poll_obj, 1, 2, poll_poll);
 
 STATIC mp_obj_t poll_ipoll(size_t n_args, const mp_obj_t *args) {
     mp_obj_poll_t *self = MP_OBJ_TO_PTR(args[0]);
@@ -304,19 +562,19 @@ STATIC mp_obj_t poll_iternext(mp_obj_t self_in) {
 
     self->iter_cnt--;
 
-    for (mp_uint_t i = self->iter_idx; i < self->poll_map.alloc; ++i) {
+    for (mp_uint_t i = self->iter_idx; i < self->poll_set.map.alloc; ++i) {
         self->iter_idx++;
-        if (!mp_map_slot_is_filled(&self->poll_map, i)) {
+        if (!mp_map_slot_is_filled(&self->poll_set.map, i)) {
             continue;
         }
-        poll_obj_t *poll_obj = MP_OBJ_TO_PTR(self->poll_map.table[i].value);
-        if (poll_obj->flags_ret != 0) {
+        poll_obj_t *poll_obj = MP_OBJ_TO_PTR(self->poll_set.map.table[i].value);
+        if (poll_obj_get_revents(poll_obj) != 0) {
             mp_obj_tuple_t *t = MP_OBJ_TO_PTR(self->ret_tuple);
             t->items[0] = poll_obj->obj;
-            t->items[1] = MP_OBJ_NEW_SMALL_INT(poll_obj->flags_ret);
+            t->items[1] = MP_OBJ_NEW_SMALL_INT(poll_obj_get_revents(poll_obj));
             if (self->flags & FLAG_ONESHOT) {
-                // Don't poll next time, until new event flags will be set explicitly
-                poll_obj->flags = 0;
+                // Don't poll next time, until new event mask will be set explicitly
+                poll_obj_set_events(poll_obj, 0);
             }
             return MP_OBJ_FROM_PTR(t);
         }
@@ -347,7 +605,7 @@ STATIC MP_DEFINE_CONST_OBJ_TYPE(
 // poll()
 STATIC mp_obj_t select_poll(void) {
     mp_obj_poll_t *poll = mp_obj_malloc(mp_obj_poll_t, &mp_type_poll);
-    mp_map_init(&poll->poll_map, 0);
+    poll_set_init(&poll->poll_set, 0);
     poll->iter_cnt = 0;
     poll->ret_tuple = MP_OBJ_NULL;
     return MP_OBJ_FROM_PTR(poll);
diff --git a/extmod/modsocket.c b/extmod/modsocket.c
index 488b6d1712..72a32e3cba 100644
--- a/extmod/modsocket.c
+++ b/extmod/modsocket.c
@@ -631,6 +631,7 @@ STATIC const mp_rom_map_elem_t mp_module_socket_globals_table[] = {
 
     { MP_ROM_QSTR(MP_QSTR_SOL_SOCKET), MP_ROM_INT(MOD_NETWORK_SOL_SOCKET) },
     { MP_ROM_QSTR(MP_QSTR_SO_REUSEADDR), MP_ROM_INT(MOD_NETWORK_SO_REUSEADDR) },
+    { MP_ROM_QSTR(MP_QSTR_SO_BROADCAST), MP_ROM_INT(MOD_NETWORK_SO_BROADCAST) },
     { MP_ROM_QSTR(MP_QSTR_SO_KEEPALIVE), MP_ROM_INT(MOD_NETWORK_SO_KEEPALIVE) },
     { MP_ROM_QSTR(MP_QSTR_SO_SNDTIMEO), MP_ROM_INT(MOD_NETWORK_SO_SNDTIMEO) },
     { MP_ROM_QSTR(MP_QSTR_SO_RCVTIMEO), MP_ROM_INT(MOD_NETWORK_SO_RCVTIMEO) },
diff --git a/extmod/modssl_mbedtls.c b/extmod/modssl_mbedtls.c
index 6d78d7d1b3..449952594c 100644
--- a/extmod/modssl_mbedtls.c
+++ b/extmod/modssl_mbedtls.c
@@ -168,6 +168,12 @@ STATIC mp_obj_t ssl_context_make_new(const mp_obj_type_t *type_in, size_t n_args
     mbedtls_debug_set_threshold(3);
     #endif
 
+    // Whenever the PSA interface is used (if MBEDTLS_PSA_CRYPTO), psa_crypto_init() needs to be called before any TLS related operations.
+    // TLSv1.3 depends on the PSA interface, TLSv1.2 only uses the PSA stack if MBEDTLS_USE_PSA_CRYPTO is defined.
+    #if defined(MBEDTLS_SSL_PROTO_TLS1_3) || defined(MBEDTLS_USE_PSA_CRYPTO)
+    psa_crypto_init();
+    #endif
+
     const byte seed[] = "upy";
     int ret = mbedtls_ctr_drbg_seed(&self->ctr_drbg, mbedtls_entropy_func, &self->entropy, seed, sizeof(seed));
     if (ret != 0) {
@@ -394,6 +400,7 @@ STATIC mp_obj_t ssl_socket_make_new(mp_obj_ssl_context_t *ssl_context, mp_obj_t
     return MP_OBJ_FROM_PTR(o);
 
 cleanup:
+    o->sock = MP_OBJ_NULL;
     mbedtls_ssl_free(&o->ssl);
     mbedtls_raise_error(ret);
 }
@@ -436,6 +443,14 @@ STATIC mp_uint_t socket_read(mp_obj_t o_in, void *buf, mp_uint_t size, int *errc
         // renegotiation.
         ret = MP_EWOULDBLOCK;
         o->poll_mask = MP_STREAM_POLL_WR;
+    #if defined(MBEDTLS_SSL_PROTO_TLS1_3)
+    } else if (ret == MBEDTLS_ERR_SSL_RECEIVED_NEW_SESSION_TICKET) {
+        // It appears a new session ticket being issued by the server right after
+        // completed handshake is not uncommon and shouldn't be treated as fatal.
+        // mbedtls itself states "This error code is experimental and may be
+        // changed or removed without notice."
+        ret = MP_EWOULDBLOCK;
+    #endif
     } else {
         o->last_error = ret;
     }
@@ -486,15 +501,20 @@ STATIC mp_uint_t socket_ioctl(mp_obj_t o_in, mp_uint_t request, uintptr_t arg, i
     mp_uint_t ret = 0;
     uintptr_t saved_arg = 0;
     mp_obj_t sock = self->sock;
-    if (sock == MP_OBJ_NULL || (request != MP_STREAM_CLOSE && self->last_error != 0)) {
-        // Closed or error socket:
-        return MP_STREAM_POLL_NVAL;
-    }
 
     if (request == MP_STREAM_CLOSE) {
+        if (sock == MP_OBJ_NULL) {
+            // Already closed socket, do nothing.
+            return 0;
+        }
         self->sock = MP_OBJ_NULL;
         mbedtls_ssl_free(&self->ssl);
     } else if (request == MP_STREAM_POLL) {
+        if (sock == MP_OBJ_NULL || self->last_error != 0) {
+            // Closed or error socket, return NVAL flag.
+            return MP_STREAM_POLL_NVAL;
+        }
+
         // If the library signaled us that it needs reading or writing, only check that direction,
         // but save what the caller asked because we need to restore it later
         if (self->poll_mask && (arg & MP_STREAM_POLL_RDWR)) {
@@ -514,6 +534,10 @@ STATIC mp_uint_t socket_ioctl(mp_obj_t o_in, mp_uint_t request, uintptr_t arg, i
                 }
             }
         }
+    } else {
+        // Unsupported ioctl.
+        *errcode = MP_EINVAL;
+        return MP_STREAM_ERROR;
     }
 
     // Pass all requests down to the underlying socket
diff --git a/extmod/vfs_posix_file.c b/extmod/vfs_posix_file.c
index cfc56df99f..488593230c 100644
--- a/extmod/vfs_posix_file.c
+++ b/extmod/vfs_posix_file.c
@@ -153,12 +153,17 @@ STATIC mp_uint_t vfs_posix_file_ioctl(mp_obj_t o_in, mp_uint_t request, uintptr_
     switch (request) {
         case MP_STREAM_FLUSH: {
             int ret;
+            // fsync(stdin/stdout/stderr) may fail with EINVAL (or ENOTSUP on macos),
+            // but don't propagate that error out.  Because data is not buffered by
+            // us, and stdin/out/err.flush() should just be a no-op.
+            #ifdef __APPLE__
+            #define VFS_POSIX_STREAM_STDIO_ERR_CATCH (err == EINVAL || err == ENOTSUP)
+            #else
+            #define VFS_POSIX_STREAM_STDIO_ERR_CATCH (err == EINVAL)
+            #endif
             MP_HAL_RETRY_SYSCALL(ret, fsync(o->fd), {
-                if (err == EINVAL
+                if (VFS_POSIX_STREAM_STDIO_ERR_CATCH
                     && (o->fd == STDIN_FILENO || o->fd == STDOUT_FILENO || o->fd == STDERR_FILENO)) {
-                    // fsync(stdin/stdout/stderr) may fail with EINVAL, but don't propagate that
-                    // error out.  Because data is not buffered by us, and stdin/out/err.flush()
-                    // should just be a no-op.
                     return 0;
                 }
                 *errcode = err;
@@ -188,7 +193,7 @@ STATIC mp_uint_t vfs_posix_file_ioctl(mp_obj_t o_in, mp_uint_t request, uintptr_
             return 0;
         case MP_STREAM_GET_FILENO:
             return o->fd;
-        #if MICROPY_PY_SELECT
+        #if MICROPY_PY_SELECT && !MICROPY_PY_SELECT_POSIX_OPTIMISATIONS
         case MP_STREAM_POLL: {
             #ifdef _WIN32
             mp_raise_NotImplementedError(MP_ERROR_TEXT("poll on file not available on win32"));
@@ -209,6 +214,15 @@ STATIC mp_uint_t vfs_posix_file_ioctl(mp_obj_t o_in, mp_uint_t request, uintptr_
                 if (pfd.revents & POLLOUT) {
                     ret |= MP_STREAM_POLL_WR;
                 }
+                if (pfd.revents & POLLERR) {
+                    ret |= MP_STREAM_POLL_ERR;
+                }
+                if (pfd.revents & POLLHUP) {
+                    ret |= MP_STREAM_POLL_HUP;
+                }
+                if (pfd.revents & POLLNVAL) {
+                    ret |= MP_STREAM_POLL_NVAL;
+                }
             }
             return ret;
             #endif
@@ -260,12 +274,58 @@ STATIC const mp_stream_p_t vfs_posix_textio_stream_p = {
     .is_text = true,
 };
 
+#if MICROPY_PY_SYS_STDIO_BUFFER
+
+const mp_obj_vfs_posix_file_t mp_sys_stdin_buffer_obj = {{&mp_type_vfs_posix_fileio}, STDIN_FILENO};
+const mp_obj_vfs_posix_file_t mp_sys_stdout_buffer_obj = {{&mp_type_vfs_posix_fileio}, STDOUT_FILENO};
+const mp_obj_vfs_posix_file_t mp_sys_stderr_buffer_obj = {{&mp_type_vfs_posix_fileio}, STDERR_FILENO};
+
+// Forward declarations.
+const mp_obj_vfs_posix_file_t mp_sys_stdin_obj;
+const mp_obj_vfs_posix_file_t mp_sys_stdout_obj;
+const mp_obj_vfs_posix_file_t mp_sys_stderr_obj;
+
+STATIC void vfs_posix_textio_attr(mp_obj_t self_in, qstr attr, mp_obj_t *dest) {
+    if (dest[0] != MP_OBJ_NULL) {
+        // These objects are read-only.
+        return;
+    }
+
+    if (attr == MP_QSTR_buffer) {
+        // Implement the `buffer` attribute only on std{in,out,err} instances.
+        if (MP_OBJ_TO_PTR(self_in) == &mp_sys_stdin_obj) {
+            dest[0] = MP_OBJ_FROM_PTR(&mp_sys_stdin_buffer_obj);
+            return;
+        }
+        if (MP_OBJ_TO_PTR(self_in) == &mp_sys_stdout_obj) {
+            dest[0] = MP_OBJ_FROM_PTR(&mp_sys_stdout_buffer_obj);
+            return;
+        }
+        if (MP_OBJ_TO_PTR(self_in) == &mp_sys_stderr_obj) {
+            dest[0] = MP_OBJ_FROM_PTR(&mp_sys_stderr_buffer_obj);
+            return;
+        }
+    }
+
+    // Any other attribute - forward to locals dict.
+    dest[1] = MP_OBJ_SENTINEL;
+};
+
+#define VFS_POSIX_TEXTIO_TYPE_ATTR attr, vfs_posix_textio_attr,
+
+#else
+
+#define VFS_POSIX_TEXTIO_TYPE_ATTR
+
+#endif // MICROPY_PY_SYS_STDIO_BUFFER
+
 MP_DEFINE_CONST_OBJ_TYPE(
     mp_type_vfs_posix_textio,
     MP_QSTR_TextIOWrapper,
     MP_TYPE_FLAG_ITER_IS_STREAM,
     print, vfs_posix_file_print,
     protocol, &vfs_posix_textio_stream_p,
+    VFS_POSIX_TEXTIO_TYPE_ATTR
     locals_dict, &vfs_posix_rawfile_locals_dict
     );
 
diff --git a/lib/uzlib/header.c b/lib/uzlib/header.c
index edd2b08ab5..9c48d91391 100644
--- a/lib/uzlib/header.c
+++ b/lib/uzlib/header.c
@@ -108,6 +108,10 @@ int uzlib_parse_zlib_gzip_header(uzlib_uncomp_t *d, int *wbits)
         d->checksum_type = UZLIB_CHKSUM_CRC;
         d->checksum = ~0;
 
+        /* gzip does not include the window size in the header, as it is expected that a
+           compressor will use wbits=15 (32kiB).*/
+        *wbits = 15;
+
         return UZLIB_HEADER_GZIP;
     } else {
        /* check checksum */
diff --git a/mpy-cross/mpy_cross/__init__.py b/mpy-cross/mpy_cross/__init__.py
index 8eadbc8352..5020033e8c 100644
--- a/mpy-cross/mpy_cross/__init__.py
+++ b/mpy-cross/mpy_cross/__init__.py
@@ -100,7 +100,7 @@ def compile(src, dest=None, src_path=None, opt=None, march=None, mpy_cross=None,
     if not src:
         raise ValueError("src is required")
     if not os.path.exists(src):
-        raise CrossCompileError("Input .py file not found: {}.".format(src_py))
+        raise CrossCompileError("Input .py file not found: {}.".format(src))
 
     args = []
 
diff --git a/ports/cc3200/Makefile b/ports/cc3200/Makefile
index 61af0bfd98..f89a927c0e 100644
--- a/ports/cc3200/Makefile
+++ b/ports/cc3200/Makefile
@@ -7,6 +7,8 @@ endif
 
 # Make 'release' the default build type
 BTYPE ?= release
+# Make the 'application' by default ('bootloader' can be built explicitly)
+BTARGET ?= application
 
 # Port for flashing firmware
 PORT ?= /dev/ttyUSB1
diff --git a/ports/cc3200/application.mk b/ports/cc3200/application.mk
index 5021e4ff3c..f4487d69d4 100644
--- a/ports/cc3200/application.mk
+++ b/ports/cc3200/application.mk
@@ -198,7 +198,7 @@ WIPY_IP ?= '192.168.1.1'
 WIPY_USER ?= 'micro'
 WIPY_PWD ?= 'python'
 
-all: $(BUILD)/mcuimg.bin
+all: $(BUILD)/firmware.zip
 
 .PHONY: deploy-ota
 
@@ -219,6 +219,10 @@ $(BUILD)/mcuimg.bin: $(BUILD)/application.bin
 	$(ECHO) "Create $@"
 	$(Q)$(SHELL) $(APP_SIGN) $(BUILD)
 
+$(BUILD)/firmware.zip: $(BUILD)/mcuimg.bin
+	$(ECHO) "Create $@"
+	$(Q)$(ZIP) -j $@ $<
+
 MAKE_PINS = boards/make-pins.py
 BOARD_PINS = boards/$(BOARD)/pins.csv
 AF_FILE = boards/cc3200_af.csv
diff --git a/ports/cc3200/boards/WIPY/board.json b/ports/cc3200/boards/WIPY/board.json
index d8293b2481..f615953af7 100644
--- a/ports/cc3200/boards/WIPY/board.json
+++ b/ports/cc3200/boards/WIPY/board.json
@@ -5,13 +5,11 @@
     "docs": "https://docs.pycom.io/datasheets/development/wipy3/",
     "features": [
         "BLE",
-        "Breadboard Friendly",
-        "MicroSD",
+        "External Flash",
         "RGB LED",
-        "SPI Flash",
-        "WiFi"
+        "WiFi",
+        "microSD"
     ],
-    "id": "wipy",
     "images": [
         "wipy.jpg"
     ],
diff --git a/ports/cc3200/mpthreadport.c b/ports/cc3200/mpthreadport.c
index 4b6f27d578..5b4771f395 100644
--- a/ports/cc3200/mpthreadport.c
+++ b/ports/cc3200/mpthreadport.c
@@ -89,6 +89,10 @@ void mp_thread_set_state(mp_state_thread_t *state) {
     vTaskSetThreadLocalStoragePointer(NULL, 0, state);
 }
 
+mp_uint_t mp_thread_get_id(void) {
+    return (mp_uint_t)xTaskGetCurrentTaskHandle();
+}
+
 void mp_thread_start(void) {
     mp_thread_mutex_lock(&thread_mutex, 1);
     for (mp_thread_t *th = thread; th != NULL; th = th->next) {
@@ -111,7 +115,7 @@ STATIC void freertos_entry(void *arg) {
     }
 }
 
-void mp_thread_create(void *(*entry)(void *), void *arg, size_t *stack_size) {
+mp_uint_t mp_thread_create(void *(*entry)(void *), void *arg, size_t *stack_size) {
     // store thread entry function into a global variable so we can access it
     ext_thread_entry = entry;
 
@@ -148,6 +152,9 @@ void mp_thread_create(void *(*entry)(void *), void *arg, size_t *stack_size) {
 
     // adjust stack_size to provide room to recover from hitting the limit
     *stack_size -= 512;
+
+    MP_STATIC_ASSERT(sizeof(mp_uint_t) >= sizeof(TaskHandle_t));
+    return (mp_uint_t)id;
 }
 
 void mp_thread_finish(void) {
diff --git a/ports/cc3200/tools/uniflash.py b/ports/cc3200/tools/uniflash.py
index 83445a12d3..2fa2c02f45 100644
--- a/ports/cc3200/tools/uniflash.py
+++ b/ports/cc3200/tools/uniflash.py
@@ -41,7 +41,7 @@ def execute(command):
     if exitCode == 0:
         return cmd_log
     else:
-        raise ProcessException(command, exitCode, output)
+        raise subprocess.CalledProcessError(exitCode, command, output)
 
 
 def main():
diff --git a/ports/esp32/CMakeLists.txt b/ports/esp32/CMakeLists.txt
index 4e29e96109..94047a0482 100644
--- a/ports/esp32/CMakeLists.txt
+++ b/ports/esp32/CMakeLists.txt
@@ -4,7 +4,7 @@ cmake_minimum_required(VERSION 3.12)
 
 # Set the board if it's not already set.
 if(NOT MICROPY_BOARD)
-    set(MICROPY_BOARD GENERIC)
+    set(MICROPY_BOARD ESP32_GENERIC)
 endif()
 
 # Set the board directory and check that it exists.
diff --git a/ports/esp32/Makefile b/ports/esp32/Makefile
index 7c8c225dfb..bf275ffe66 100644
--- a/ports/esp32/Makefile
+++ b/ports/esp32/Makefile
@@ -8,17 +8,25 @@ ifdef BOARD_DIR
 # the path as the board name.
 BOARD ?= $(notdir $(BOARD_DIR:/=))
 else
-# If not given on the command line, then default to GENERIC.
-BOARD ?= GENERIC
+# If not given on the command line, then default to ESP32_GENERIC.
+BOARD ?= ESP32_GENERIC
 BOARD_DIR ?= boards/$(BOARD)
 endif
 
 ifeq ($(wildcard $(BOARD_DIR)/.),)
+ifeq ($(findstring boards/GENERIC,$(BOARD_DIR)),boards/GENERIC)
+$(warning The GENERIC* boards have been renamed to ESP32_GENERIC*)
+endif
 $(error Invalid BOARD specified: $(BOARD_DIR))
 endif
 
-# If the build directory is not given, make it reflect the board name.
+# If the build directory is not given, make it reflect the board name (and
+# optionally the board variant).
+ifneq ($(BOARD_VARIANT),)
+BUILD ?= build-$(BOARD)-$(BOARD_VARIANT)
+else
 BUILD ?= build-$(BOARD)
+endif
 
 # Device serial settings.
 PORT ?= /dev/ttyUSB0
@@ -26,12 +34,6 @@ BAUD ?= 460800
 
 PYTHON ?= python3
 
-# Would be good to use cmake to discover submodules (see how rp2/Makefile does
-# it), but on ESP32 the same trick doesn't work because "idf.py build" fails
-# on berkeley-db dependency before printing out the submodule list.
-# For now just force the submodule dependencies here.
-GIT_SUBMODULES += lib/berkeley-db-1.xx lib/micropython-lib
-
 .PHONY: all clean deploy erase submodules FORCE
 
 CMAKE_ARGS =
@@ -40,20 +42,24 @@ ifdef USER_C_MODULES
 	CMAKE_ARGS += -DUSER_C_MODULES=${USER_C_MODULES}
 endif
 
-IDFPY_FLAGS += -D MICROPY_BOARD=$(BOARD) -D MICROPY_BOARD_DIR=$(abspath $(BOARD_DIR)) -B $(BUILD) $(CMAKE_ARGS)
+IDFPY_FLAGS += -D MICROPY_BOARD=$(BOARD) -D MICROPY_BOARD_DIR=$(abspath $(BOARD_DIR)) $(CMAKE_ARGS)
 
 ifdef FROZEN_MANIFEST
        IDFPY_FLAGS += -D MICROPY_FROZEN_MANIFEST=$(FROZEN_MANIFEST)
 endif
 
+ifdef BOARD_VARIANT
+	IDFPY_FLAGS += -D MICROPY_BOARD_VARIANT=$(BOARD_VARIANT)
+endif
+
 HELP_BUILD_ERROR ?= "See \033[1;31mhttps://github.com/micropython/micropython/wiki/Build-Troubleshooting\033[0m"
 
 define RUN_IDF_PY
-	idf.py $(IDFPY_FLAGS) -p $(PORT) -b $(BAUD) $(1)
+	idf.py $(IDFPY_FLAGS) -B $(BUILD) -p $(PORT) -b $(BAUD) $(1)
 endef
 
 all:
-	idf.py $(IDFPY_FLAGS) build || (echo -e $(HELP_BUILD_ERROR); false)
+	idf.py $(IDFPY_FLAGS) -B $(BUILD) build || (echo -e $(HELP_BUILD_ERROR); false)
 	@$(PYTHON) makeimg.py \
 		$(BUILD)/sdkconfig \
 		$(BUILD)/bootloader/bootloader.bin \
@@ -85,5 +91,12 @@ size-components:
 size-files:
 	$(call RUN_IDF_PY,size-files)
 
+# Running the build with ECHO_SUBMODULES set will trigger py/mkrules.cmake to
+# print out the value of the GIT_SUBMODULES variable, prefixed with
+# "GIT_SUBMODULES", and then abort. This extracts out that line from the idf.py
+# output and passes the list of submodules to py/mkrules.mk which does the
+# `git submodule init` on each.
 submodules:
-	$(MAKE) -f ../../py/mkrules.mk GIT_SUBMODULES="$(GIT_SUBMODULES)" submodules
+	@GIT_SUBMODULES=$$(idf.py $(IDFPY_FLAGS) -B $(BUILD)/submodules -D ECHO_SUBMODULES=1 build 2>&1 | \
+	                  grep '^GIT_SUBMODULES=' | cut -d= -f2); \
+	$(MAKE) -f ../../py/mkrules.mk GIT_SUBMODULES="$${GIT_SUBMODULES}" submodules
diff --git a/ports/esp32/README.md b/ports/esp32/README.md
index 2d5b05b926..169de4073b 100644
--- a/ports/esp32/README.md
+++ b/ports/esp32/README.md
@@ -93,7 +93,7 @@ $ make submodules
 $ make
 ```
 
-This will produce a combined `firmware.bin` image in the `build-GENERIC/`
+This will produce a combined `firmware.bin` image in the `build-ESP32_GENERIC/`
 subdirectory (this firmware image is made up of: bootloader.bin, partitions.bin
 and micropython.bin).
 
@@ -123,12 +123,12 @@ To flash the MicroPython firmware to your ESP32 use:
 $ make deploy
 ```
 
-The default ESP32 board build by the above commands is the `GENERIC` one, which
-should work on most ESP32 modules.  You can specify a different board by passing
-`BOARD=<board>` to the make commands, for example:
+The default ESP32 board build by the above commands is the `ESP32_GENERIC`
+one, which should work on most ESP32 modules.  You can specify a different
+board by passing `BOARD=<board>` to the make commands, for example:
 
 ```bash
-$ make BOARD=GENERIC_SPIRAM
+$ make BOARD=ESP32_GENERIC_S3
 ```
 
 Note: the above "make" commands are thin wrappers for the underlying `idf.py`
@@ -137,10 +137,25 @@ for example:
 
 ```bash
 $ idf.py build
-$ idf.py -D MICROPY_BOARD=GENERIC_SPIRAM build
+$ idf.py -D MICROPY_BOARD=ESP32_GENERIC build
 $ idf.py flash
 ```
 
+Some boards also support "variants", which are allow for small variations of
+an otherwise similar board. For example different flash sizes or features. For
+example to build the `OTA` variant of `ESP32_GENERIC`.
+
+```bash
+$ make BOARD=ESP32_GENERIC BOARD_VARIANT=OTA
+```
+
+or to enable octal-SPIRAM support for the `ESP32_GENERIC_S3` board:
+
+```bash
+$ make BOARD=ESP32_GENERIC BOARD_VARIANT=SPIRAM_OCT
+```
+
+
 Getting a Python prompt on the device
 -------------------------------------
 
@@ -202,10 +217,10 @@ antenna = machine.Pin(16, machine.Pin.OUT, value=0)
 Defining a custom ESP32 board
 -----------------------------
 
-The default ESP-IDF configuration settings are provided by the `GENERIC`
-board definition in the directory `boards/GENERIC`. For a custom configuration
+The default ESP-IDF configuration settings are provided by the `ESP32_GENERIC`
+board definition in the directory `boards/ESP32_GENERIC`. For a custom configuration
 you can define your own board directory.  Start a new board configuration by
-copying an existing one (like `GENERIC`) and modifying it to suit your board.
+copying an existing one (like `ESP32_GENERIC`) and modifying it to suit your board.
 
 MicroPython specific configuration values are defined in the board-specific
 `mpconfigboard.h` file, which is included by `mpconfigport.h`.  Additional
diff --git a/ports/esp32/boards/ARDUINO_NANO_ESP32/board.json b/ports/esp32/boards/ARDUINO_NANO_ESP32/board.json
index afb24e1049..77aa192959 100644
--- a/ports/esp32/boards/ARDUINO_NANO_ESP32/board.json
+++ b/ports/esp32/boards/ARDUINO_NANO_ESP32/board.json
@@ -5,9 +5,10 @@
     "docs": "",
     "features": [
         "BLE",
-        "WiFi",
+        "External Flash",
+        "RGB LED",
         "USB-C",
-        "RGB LED"
+        "WiFi"
     ],
     "images": [
         "ABX00092_01.iso_1000x750.jpg"
diff --git a/ports/esp32/boards/ARDUINO_NANO_ESP32/deploy.md b/ports/esp32/boards/ARDUINO_NANO_ESP32/deploy.md
index b600a55b64..bb32ba7559 100644
--- a/ports/esp32/boards/ARDUINO_NANO_ESP32/deploy.md
+++ b/ports/esp32/boards/ARDUINO_NANO_ESP32/deploy.md
@@ -4,5 +4,10 @@ This board can programmed via DFU bootloader, using e.g. [dfu-util](http://dfu-u
 To enter the DFU bootloader, double tap the reset (blue) button, or you can use `machine.bootloader()` from the MicroPython REPL.
 
 ```bash
-dfu-util -d 0x2341:0x0070 -R -D build-ARDUINO_NANO_ESP32/micropython.bin
+dfu-util -d 0x2341:0x0070 -R -D build-ARDUINO_NANO_ESP32/micropython.app-bin
 ```
+
+Please note that the DFU bootloader comes factory flashed. Should you for any reason erase the
+entire flash, the DFU bootloader will have to be re-installed. Please follow the instructions
+[here](https://support.arduino.cc/hc/en-us/articles/9810414060188-Reset-the-Arduino-bootloader-on-the-Nano-ESP32)
+to do so.
diff --git a/ports/esp32/boards/GENERIC/board.json b/ports/esp32/boards/ESP32_GENERIC/board.json
similarity index 56%
rename from ports/esp32/boards/GENERIC/board.json
rename to ports/esp32/boards/ESP32_GENERIC/board.json
index a52d58007d..0db38c25d3 100644
--- a/ports/esp32/boards/GENERIC/board.json
+++ b/ports/esp32/boards/ESP32_GENERIC/board.json
@@ -5,18 +5,22 @@
     "docs": "",
     "features": [
         "BLE",
+        "External Flash",
         "WiFi"
     ],
-    "id": "esp32",
     "images": [
         "esp32_devkitc.jpg"
     ],
     "mcu": "esp32",
-    "product": "ESP32",
+    "product": "ESP32 / WROOM",
     "thumbnail": "",
     "url": "https://www.espressif.com/en/products/modules",
     "variants": {
-        "idf3": "Compiled with IDF 3.x"
+        "IDF3": "Compiled with IDF 3.x",
+        "D2WD": "ESP32 D2WD",
+        "SPIRAM": "Support for SPIRAM / WROVER",
+        "UNICORE": "ESP32 Unicore",
+        "OTA": "Support for OTA"
     },
     "vendor": "Espressif"
 }
diff --git a/ports/esp32/boards/ESP32_GENERIC/board.md b/ports/esp32/boards/ESP32_GENERIC/board.md
new file mode 100644
index 0000000000..8a669411d0
--- /dev/null
+++ b/ports/esp32/boards/ESP32_GENERIC/board.md
@@ -0,0 +1,9 @@
+The following files are firmware that should work on most ESP32-based boards
+with 4MiB of flash, including WROOM WROVER, SOLO, PICO, and MINI modules.
+
+If your board is based on a WROVER module, or otherwise has SPIRAM (also known
+as PSRAM), then use the "spiram" variant.
+
+The "d2wd" variant is for ESP32-D2WD chips (with 2MiB flash), and "unicore" is
+for single-core ESP32 chips (e.g. the "SOLO" modules). The "ota" variant sets
+up the partition table to allow for Over-the-Air updates.
diff --git a/ports/esp32/boards/ESP32_GENERIC/mpconfigboard.cmake b/ports/esp32/boards/ESP32_GENERIC/mpconfigboard.cmake
new file mode 100644
index 0000000000..74cb591c07
--- /dev/null
+++ b/ports/esp32/boards/ESP32_GENERIC/mpconfigboard.cmake
@@ -0,0 +1,48 @@
+set(SDKCONFIG_DEFAULTS
+    boards/sdkconfig.base
+    boards/sdkconfig.ble
+)
+
+if(MICROPY_BOARD_VARIANT STREQUAL "D2WD")
+    set(SDKCONFIG_DEFAULTS
+        ${SDKCONFIG_DEFAULTS}
+        boards/ESP32_GENERIC/sdkconfig.d2wd
+    )
+
+    list(APPEND MICROPY_DEF_BOARD
+        MICROPY_HW_MCU_NAME="ESP32-D2WD"
+    )
+endif()
+
+if(MICROPY_BOARD_VARIANT STREQUAL "OTA")
+    set(SDKCONFIG_DEFAULTS
+        ${SDKCONFIG_DEFAULTS}
+        boards/ESP32_GENERIC/sdkconfig.ota
+    )
+
+    list(APPEND MICROPY_DEF_BOARD
+        MICROPY_HW_BOARD_NAME="Generic ESP32 module with OTA"
+    )
+endif()
+
+if(MICROPY_BOARD_VARIANT STREQUAL "SPIRAM")
+    set(SDKCONFIG_DEFAULTS
+        ${SDKCONFIG_DEFAULTS}
+        boards/sdkconfig.spiram
+    )
+
+    list(APPEND MICROPY_DEF_BOARD
+        MICROPY_HW_BOARD_NAME="Generic ESP32 module with SPIRAM"
+    )
+endif()
+
+if(MICROPY_BOARD_VARIANT STREQUAL "UNICORE")
+    set(SDKCONFIG_DEFAULTS
+        ${SDKCONFIG_DEFAULTS}
+        boards/ESP32_GENERIC/sdkconfig.unicore
+    )
+
+    list(APPEND MICROPY_DEF_BOARD
+        MICROPY_HW_MCU_NAME="ESP32-UNICORE"
+    )
+endif()
diff --git a/ports/esp32/boards/ESP32_GENERIC/mpconfigboard.h b/ports/esp32/boards/ESP32_GENERIC/mpconfigboard.h
new file mode 100644
index 0000000000..7171a84bb3
--- /dev/null
+++ b/ports/esp32/boards/ESP32_GENERIC/mpconfigboard.h
@@ -0,0 +1,10 @@
+// Both of these can be set by mpconfigboard.cmake if a BOARD_VARIANT is
+// specified.
+
+#ifndef MICROPY_HW_BOARD_NAME
+#define MICROPY_HW_BOARD_NAME "Generic ESP32 module"
+#endif
+
+#ifndef MICROPY_HW_MCU_NAME
+#define MICROPY_HW_MCU_NAME "ESP32"
+#endif
diff --git a/ports/esp32/boards/GENERIC_D2WD/sdkconfig.board b/ports/esp32/boards/ESP32_GENERIC/sdkconfig.d2wd
similarity index 100%
rename from ports/esp32/boards/GENERIC_D2WD/sdkconfig.board
rename to ports/esp32/boards/ESP32_GENERIC/sdkconfig.d2wd
diff --git a/ports/esp32/boards/GENERIC_OTA/sdkconfig.board b/ports/esp32/boards/ESP32_GENERIC/sdkconfig.ota
similarity index 72%
rename from ports/esp32/boards/GENERIC_OTA/sdkconfig.board
rename to ports/esp32/boards/ESP32_GENERIC/sdkconfig.ota
index 7ff939aa99..4a164aa6f8 100644
--- a/ports/esp32/boards/GENERIC_OTA/sdkconfig.board
+++ b/ports/esp32/boards/ESP32_GENERIC/sdkconfig.ota
@@ -1,6 +1,6 @@
 CONFIG_BOOTLOADER_APP_ROLLBACK_ENABLE=y
 CONFIG_PARTITION_TABLE_CUSTOM=y
-CONFIG_PARTITION_TABLE_CUSTOM_FILENAME="partitions-ota.csv"
+CONFIG_PARTITION_TABLE_CUSTOM_FILENAME="partitions-4MiB-ota.csv"
 
 # Reduce firmware size to fit in the OTA partition.
 CONFIG_COMPILER_OPTIMIZATION_CHECKS_SILENT=y
diff --git a/ports/esp32/boards/GENERIC_UNICORE/sdkconfig.board b/ports/esp32/boards/ESP32_GENERIC/sdkconfig.unicore
similarity index 100%
rename from ports/esp32/boards/GENERIC_UNICORE/sdkconfig.board
rename to ports/esp32/boards/ESP32_GENERIC/sdkconfig.unicore
diff --git a/ports/esp32/boards/GENERIC_C3/board.json b/ports/esp32/boards/ESP32_GENERIC_C3/board.json
similarity index 92%
rename from ports/esp32/boards/GENERIC_C3/board.json
rename to ports/esp32/boards/ESP32_GENERIC_C3/board.json
index 6cc326bf14..4a81d227a0 100644
--- a/ports/esp32/boards/GENERIC_C3/board.json
+++ b/ports/esp32/boards/ESP32_GENERIC_C3/board.json
@@ -5,9 +5,9 @@
     "docs": "",
     "features": [
         "BLE",
+        "External Flash",
         "WiFi"
     ],
-    "id": "esp32c3",
     "images": [
         "esp32c3_devkitmini.jpg"
     ],
diff --git a/ports/esp32/boards/ESP32_GENERIC_C3/board.md b/ports/esp32/boards/ESP32_GENERIC_C3/board.md
new file mode 100644
index 0000000000..1604b879c5
--- /dev/null
+++ b/ports/esp32/boards/ESP32_GENERIC_C3/board.md
@@ -0,0 +1,7 @@
+The following files are firmware images that should work on most
+ESP32-C3-based boards with 4MiB of flash, including WROOM and MINI modules,
+that use the revision 3 silicon (or newer).
+
+USB serial/JTAG support is enabled on pin 18 and 19. Note that this
+is not a full USB stack, the C3 just provides a CDC/ACM class serial
+and JTAG interface.
diff --git a/ports/esp32/boards/GENERIC_C3/mpconfigboard.cmake b/ports/esp32/boards/ESP32_GENERIC_C3/mpconfigboard.cmake
similarity index 69%
rename from ports/esp32/boards/GENERIC_C3/mpconfigboard.cmake
rename to ports/esp32/boards/ESP32_GENERIC_C3/mpconfigboard.cmake
index 38bf7388fa..429366afac 100644
--- a/ports/esp32/boards/GENERIC_C3/mpconfigboard.cmake
+++ b/ports/esp32/boards/ESP32_GENERIC_C3/mpconfigboard.cmake
@@ -3,4 +3,5 @@ set(IDF_TARGET esp32c3)
 set(SDKCONFIG_DEFAULTS
     boards/sdkconfig.base
     boards/sdkconfig.ble
+    boards/ESP32_GENERIC_C3/sdkconfig.c3usb
 )
diff --git a/ports/esp32/boards/GENERIC_C3/mpconfigboard.h b/ports/esp32/boards/ESP32_GENERIC_C3/mpconfigboard.h
similarity index 71%
rename from ports/esp32/boards/GENERIC_C3/mpconfigboard.h
rename to ports/esp32/boards/ESP32_GENERIC_C3/mpconfigboard.h
index d403e70e46..42e77ecb1a 100644
--- a/ports/esp32/boards/GENERIC_C3/mpconfigboard.h
+++ b/ports/esp32/boards/ESP32_GENERIC_C3/mpconfigboard.h
@@ -6,3 +6,6 @@
 #define MICROPY_HW_ENABLE_SDCARD            (0)
 #define MICROPY_PY_MACHINE_DAC              (0)
 #define MICROPY_PY_MACHINE_I2S              (0)
+
+// Enable UART REPL for modules that have an external USB-UART and don't use native USB.
+#define MICROPY_HW_ENABLE_UART_REPL         (1)
diff --git a/ports/esp32/boards/GENERIC_C3_USB/sdkconfig.board b/ports/esp32/boards/ESP32_GENERIC_C3/sdkconfig.c3usb
similarity index 100%
rename from ports/esp32/boards/GENERIC_C3_USB/sdkconfig.board
rename to ports/esp32/boards/ESP32_GENERIC_C3/sdkconfig.c3usb
diff --git a/ports/esp32/boards/GENERIC_S2/board.json b/ports/esp32/boards/ESP32_GENERIC_S2/board.json
similarity index 86%
rename from ports/esp32/boards/GENERIC_S2/board.json
rename to ports/esp32/boards/ESP32_GENERIC_S2/board.json
index dbd3b5b015..35d06f2f7e 100644
--- a/ports/esp32/boards/GENERIC_S2/board.json
+++ b/ports/esp32/boards/ESP32_GENERIC_S2/board.json
@@ -5,6 +5,8 @@
     "docs": "",
     "features": [
         "BLE",
+        "External Flash",
+        "External RAM",
         "WiFi"
     ],
     "images": [
diff --git a/ports/esp32/boards/ESP32_GENERIC_S2/board.md b/ports/esp32/boards/ESP32_GENERIC_S2/board.md
new file mode 100644
index 0000000000..3e46c02467
--- /dev/null
+++ b/ports/esp32/boards/ESP32_GENERIC_S2/board.md
@@ -0,0 +1,6 @@
+The following files are firmware that should work on most ESP32-S2-based
+boards with 4MiB of flash, including WROOM, WROVER, and MINI modules.
+
+This firmware supports configurations with and without SPIRAM (also known as
+PSRAM) and will auto-detect a connected SPIRAM chip at startup and allocate
+the MicroPython heap accordingly.
diff --git a/ports/esp32/boards/GENERIC_S2/mpconfigboard.cmake b/ports/esp32/boards/ESP32_GENERIC_S2/mpconfigboard.cmake
similarity index 76%
rename from ports/esp32/boards/GENERIC_S2/mpconfigboard.cmake
rename to ports/esp32/boards/ESP32_GENERIC_S2/mpconfigboard.cmake
index 59ca906f4d..76d185d90d 100644
--- a/ports/esp32/boards/GENERIC_S2/mpconfigboard.cmake
+++ b/ports/esp32/boards/ESP32_GENERIC_S2/mpconfigboard.cmake
@@ -3,4 +3,5 @@ set(IDF_TARGET esp32s2)
 set(SDKCONFIG_DEFAULTS
     boards/sdkconfig.base
     boards/sdkconfig.usb
+    boards/sdkconfig.spiram_sx
 )
diff --git a/ports/esp32/boards/ESP32_GENERIC_S2/mpconfigboard.h b/ports/esp32/boards/ESP32_GENERIC_S2/mpconfigboard.h
new file mode 100644
index 0000000000..aaea41bcde
--- /dev/null
+++ b/ports/esp32/boards/ESP32_GENERIC_S2/mpconfigboard.h
@@ -0,0 +1,8 @@
+#define MICROPY_HW_BOARD_NAME "Generic ESP32S2 module"
+#define MICROPY_HW_MCU_NAME "ESP32S2"
+
+#define MICROPY_PY_BLUETOOTH (0)
+#define MICROPY_HW_ENABLE_SDCARD (0)
+
+// Enable UART REPL for modules that have an external USB-UART and don't use native USB.
+#define MICROPY_HW_ENABLE_UART_REPL         (1)
diff --git a/ports/esp32/boards/GENERIC_S3/board.json b/ports/esp32/boards/ESP32_GENERIC_S3/board.json
similarity index 66%
rename from ports/esp32/boards/GENERIC_S3/board.json
rename to ports/esp32/boards/ESP32_GENERIC_S3/board.json
index 0db9b32503..671936c922 100644
--- a/ports/esp32/boards/GENERIC_S3/board.json
+++ b/ports/esp32/boards/ESP32_GENERIC_S3/board.json
@@ -5,6 +5,8 @@
     "docs": "",
     "features": [
         "BLE",
+        "External Flash",
+        "External RAM",
         "WiFi"
     ],
     "images": [
@@ -14,5 +16,8 @@
     "product": "ESP32-S3",
     "thumbnail": "",
     "url": "https://www.espressif.com/en/products/modules",
-    "vendor": "Espressif"
+    "vendor": "Espressif",
+    "variants": {
+        "SPIRAM_OCT": "Support for Octal-SPIRAM"
+    }
 }
diff --git a/ports/esp32/boards/ESP32_GENERIC_S3/board.md b/ports/esp32/boards/ESP32_GENERIC_S3/board.md
new file mode 100644
index 0000000000..cc902eeb89
--- /dev/null
+++ b/ports/esp32/boards/ESP32_GENERIC_S3/board.md
@@ -0,0 +1,7 @@
+The following files are firmware that should work on most ESP32-S3-based
+boards with 8MiB of flash, including WROOM and MINI modules.
+
+This firmware supports configurations with and without SPIRAM (also known as
+PSRAM) and will auto-detect a connected SPIRAM chip at startup and allocate
+the MicroPython heap accordingly. However if your board has Octal SPIRAM, then
+use the "spiram-oct" variant.
diff --git a/ports/esp32/boards/ESP32_GENERIC_S3/mpconfigboard.cmake b/ports/esp32/boards/ESP32_GENERIC_S3/mpconfigboard.cmake
new file mode 100644
index 0000000000..36b4fe5624
--- /dev/null
+++ b/ports/esp32/boards/ESP32_GENERIC_S3/mpconfigboard.cmake
@@ -0,0 +1,21 @@
+set(IDF_TARGET esp32s3)
+
+set(SDKCONFIG_DEFAULTS
+    boards/sdkconfig.base
+    boards/sdkconfig.usb
+    boards/sdkconfig.ble
+    boards/sdkconfig.spiram_sx
+    boards/ESP32_GENERIC_S3/sdkconfig.board
+)
+
+if(MICROPY_BOARD_VARIANT STREQUAL "SPIRAM_OCT")
+    set(SDKCONFIG_DEFAULTS
+        ${SDKCONFIG_DEFAULTS}
+        boards/sdkconfig.240mhz
+        boards/sdkconfig.spiram_oct
+    )
+
+    list(APPEND MICROPY_DEF_BOARD
+        MICROPY_HW_BOARD_NAME="Generic ESP32S3 module with Octal-SPIRAM"
+    )
+endif()
diff --git a/ports/esp32/boards/GENERIC_S3_SPIRAM/mpconfigboard.h b/ports/esp32/boards/ESP32_GENERIC_S3/mpconfigboard.h
similarity index 70%
rename from ports/esp32/boards/GENERIC_S3_SPIRAM/mpconfigboard.h
rename to ports/esp32/boards/ESP32_GENERIC_S3/mpconfigboard.h
index 1a8560a2d7..8d369c7db0 100644
--- a/ports/esp32/boards/GENERIC_S3_SPIRAM/mpconfigboard.h
+++ b/ports/esp32/boards/ESP32_GENERIC_S3/mpconfigboard.h
@@ -1,4 +1,7 @@
-#define MICROPY_HW_BOARD_NAME               "ESP32S3 module (spiram)"
+#ifndef MICROPY_HW_BOARD_NAME
+// Can be set by mpconfigboard.cmake.
+#define MICROPY_HW_BOARD_NAME               "Generic ESP32S3 module"
+#endif
 #define MICROPY_HW_MCU_NAME                 "ESP32S3"
 
 #define MICROPY_PY_MACHINE_DAC              (0)
diff --git a/ports/esp32/boards/GENERIC_S3_SPIRAM_OCT/sdkconfig.board b/ports/esp32/boards/ESP32_GENERIC_S3/sdkconfig.board
similarity index 100%
rename from ports/esp32/boards/GENERIC_S3_SPIRAM_OCT/sdkconfig.board
rename to ports/esp32/boards/ESP32_GENERIC_S3/sdkconfig.board
diff --git a/ports/esp32/boards/ESP32_S2_WROVER/board.json b/ports/esp32/boards/ESP32_S2_WROVER/board.json
deleted file mode 100644
index 7ebc84415c..0000000000
--- a/ports/esp32/boards/ESP32_S2_WROVER/board.json
+++ /dev/null
@@ -1,19 +0,0 @@
-{
-    "deploy": [
-        "../deploy_s2.md"
-    ],
-    "docs": "",
-    "features": [
-        "BLE",
-        "SPIRAM",
-        "WiFi"
-    ],
-    "images": [
-        "ESP32-S2-WROVER_L_0.jpg"
-    ],
-    "mcu": "esp32s2",
-    "product": "ESP32-S2 WROVER",
-    "thumbnail": "",
-    "url": "https://www.espressif.com/en/products/modules",
-    "vendor": "Espressif"
-}
diff --git a/ports/esp32/boards/ESP32_S2_WROVER/mpconfigboard.cmake b/ports/esp32/boards/ESP32_S2_WROVER/mpconfigboard.cmake
deleted file mode 100644
index 056c9ab4a6..0000000000
--- a/ports/esp32/boards/ESP32_S2_WROVER/mpconfigboard.cmake
+++ /dev/null
@@ -1,8 +0,0 @@
-set(IDF_TARGET esp32s2)
-
-set(SDKCONFIG_DEFAULTS
-    boards/sdkconfig.base
-    boards/sdkconfig.spiram_sx
-    boards/sdkconfig.usb
-    boards/ESP32_S2_WROVER/sdkconfig.board
-)
diff --git a/ports/esp32/boards/ESP32_S2_WROVER/mpconfigboard.h b/ports/esp32/boards/ESP32_S2_WROVER/mpconfigboard.h
deleted file mode 100644
index a96262c607..0000000000
--- a/ports/esp32/boards/ESP32_S2_WROVER/mpconfigboard.h
+++ /dev/null
@@ -1,8 +0,0 @@
-#define MICROPY_HW_BOARD_NAME               "ESP32-S2-WROVER"
-#define MICROPY_HW_MCU_NAME                 "ESP32-S2"
-
-#define MICROPY_PY_BLUETOOTH                (0)
-#define MICROPY_HW_ENABLE_SDCARD            (0)
-
-#define MICROPY_HW_I2C0_SCL                 (7)
-#define MICROPY_HW_I2C0_SDA                 (6)
diff --git a/ports/esp32/boards/ESP32_S2_WROVER/sdkconfig.board b/ports/esp32/boards/ESP32_S2_WROVER/sdkconfig.board
deleted file mode 100644
index 40a8e3047c..0000000000
--- a/ports/esp32/boards/ESP32_S2_WROVER/sdkconfig.board
+++ /dev/null
@@ -1,10 +0,0 @@
-CONFIG_ESPTOOLPY_FLASHMODE_QIO=y
-CONFIG_ESPTOOLPY_FLASHFREQ_80M=y
-CONFIG_ESPTOOLPY_AFTER_NORESET=y
-
-CONFIG_ESPTOOLPY_FLASHSIZE_4MB=y
-CONFIG_USB_AND_UART=y
-
-# LWIP
-CONFIG_LWIP_LOCAL_HOSTNAME="ESP32-S2-WROVER"
-# end of LWIP
diff --git a/ports/esp32/boards/GENERIC/board.md b/ports/esp32/boards/GENERIC/board.md
deleted file mode 100644
index efb2b2cab7..0000000000
--- a/ports/esp32/boards/GENERIC/board.md
+++ /dev/null
@@ -1 +0,0 @@
-The following files are firmware for ESP32-based boards without external SPIRAM.
diff --git a/ports/esp32/boards/GENERIC/mpconfigboard.cmake b/ports/esp32/boards/GENERIC/mpconfigboard.cmake
deleted file mode 100644
index ac60dc8630..0000000000
--- a/ports/esp32/boards/GENERIC/mpconfigboard.cmake
+++ /dev/null
@@ -1,4 +0,0 @@
-set(SDKCONFIG_DEFAULTS
-    boards/sdkconfig.base
-    boards/sdkconfig.ble
-)
diff --git a/ports/esp32/boards/GENERIC/mpconfigboard.h b/ports/esp32/boards/GENERIC/mpconfigboard.h
deleted file mode 100644
index 644807f78e..0000000000
--- a/ports/esp32/boards/GENERIC/mpconfigboard.h
+++ /dev/null
@@ -1,2 +0,0 @@
-#define MICROPY_HW_BOARD_NAME "ESP32 module"
-#define MICROPY_HW_MCU_NAME "ESP32"
diff --git a/ports/esp32/boards/GENERIC_C3_USB/board.json b/ports/esp32/boards/GENERIC_C3_USB/board.json
deleted file mode 100644
index 23f9a8eb20..0000000000
--- a/ports/esp32/boards/GENERIC_C3_USB/board.json
+++ /dev/null
@@ -1,19 +0,0 @@
-{
-    "deploy": [
-        "../deploy_c3.md"
-    ],
-    "docs": "",
-    "features": [
-        "BLE",
-        "WiFi"
-    ],
-    "id": "esp32c3-usb",
-    "images": [
-        "esp32c3_devkitmini.jpg"
-    ],
-    "mcu": "esp32c3",
-    "product": "ESP32-C3 with USB",
-    "thumbnail": "",
-    "url": "https://www.espressif.com/en/products/modules",
-    "vendor": "Espressif"
-}
diff --git a/ports/esp32/boards/GENERIC_C3_USB/mpconfigboard.cmake b/ports/esp32/boards/GENERIC_C3_USB/mpconfigboard.cmake
deleted file mode 100644
index 7436eead87..0000000000
--- a/ports/esp32/boards/GENERIC_C3_USB/mpconfigboard.cmake
+++ /dev/null
@@ -1,7 +0,0 @@
-set(IDF_TARGET esp32c3)
-
-set(SDKCONFIG_DEFAULTS
-    boards/sdkconfig.base
-    boards/sdkconfig.ble
-    boards/GENERIC_C3_USB/sdkconfig.board
-)
diff --git a/ports/esp32/boards/GENERIC_C3_USB/mpconfigboard.h b/ports/esp32/boards/GENERIC_C3_USB/mpconfigboard.h
deleted file mode 100644
index d403e70e46..0000000000
--- a/ports/esp32/boards/GENERIC_C3_USB/mpconfigboard.h
+++ /dev/null
@@ -1,8 +0,0 @@
-// This configuration is for a generic ESP32C3 board with 4MiB (or more) of flash.
-
-#define MICROPY_HW_BOARD_NAME               "ESP32C3 module"
-#define MICROPY_HW_MCU_NAME                 "ESP32C3"
-
-#define MICROPY_HW_ENABLE_SDCARD            (0)
-#define MICROPY_PY_MACHINE_DAC              (0)
-#define MICROPY_PY_MACHINE_I2S              (0)
diff --git a/ports/esp32/boards/GENERIC_D2WD/board.json b/ports/esp32/boards/GENERIC_D2WD/board.json
deleted file mode 100644
index 39fce46bca..0000000000
--- a/ports/esp32/boards/GENERIC_D2WD/board.json
+++ /dev/null
@@ -1,19 +0,0 @@
-{
-    "deploy": [
-        "../deploy.md"
-    ],
-    "docs": "",
-    "features": [
-        "BLE",
-        "WiFi"
-    ],
-    "id": "esp32-d2wd",
-    "images": [
-        "generic_d2wd.jpg"
-    ],
-    "mcu": "esp32",
-    "product": "ESP32 D2WD",
-    "thumbnail": "",
-    "url": "https://www.espressif.com/en/products/modules",
-    "vendor": "Espressif"
-}
diff --git a/ports/esp32/boards/GENERIC_D2WD/mpconfigboard.cmake b/ports/esp32/boards/GENERIC_D2WD/mpconfigboard.cmake
deleted file mode 100644
index 88cc7a730e..0000000000
--- a/ports/esp32/boards/GENERIC_D2WD/mpconfigboard.cmake
+++ /dev/null
@@ -1,5 +0,0 @@
-set(SDKCONFIG_DEFAULTS
-    boards/sdkconfig.base
-    boards/sdkconfig.ble
-    boards/GENERIC_D2WD/sdkconfig.board
-)
diff --git a/ports/esp32/boards/GENERIC_D2WD/mpconfigboard.h b/ports/esp32/boards/GENERIC_D2WD/mpconfigboard.h
deleted file mode 100644
index 8923d46fd1..0000000000
--- a/ports/esp32/boards/GENERIC_D2WD/mpconfigboard.h
+++ /dev/null
@@ -1,2 +0,0 @@
-#define MICROPY_HW_BOARD_NAME "Generic ESP32-D2WD module"
-#define MICROPY_HW_MCU_NAME "ESP32-D2WD"
diff --git a/ports/esp32/boards/GENERIC_OTA/board.json b/ports/esp32/boards/GENERIC_OTA/board.json
deleted file mode 100644
index 97756a9fb2..0000000000
--- a/ports/esp32/boards/GENERIC_OTA/board.json
+++ /dev/null
@@ -1,19 +0,0 @@
-{
-    "deploy": [
-        "../deploy.md"
-    ],
-    "docs": "",
-    "features": [
-        "BLE",
-        "WiFi"
-    ],
-    "id": "esp32-ota",
-    "images": [
-        "esp32_devkitc.jpg"
-    ],
-    "mcu": "esp32",
-    "product": "ESP32 with OTA support",
-    "thumbnail": "",
-    "url": "https://www.espressif.com/en/products/modules",
-    "vendor": "Espressif"
-}
diff --git a/ports/esp32/boards/GENERIC_OTA/mpconfigboard.cmake b/ports/esp32/boards/GENERIC_OTA/mpconfigboard.cmake
deleted file mode 100644
index 8bc9d507af..0000000000
--- a/ports/esp32/boards/GENERIC_OTA/mpconfigboard.cmake
+++ /dev/null
@@ -1,5 +0,0 @@
-set(SDKCONFIG_DEFAULTS
-    boards/sdkconfig.base
-    boards/sdkconfig.ble
-    boards/GENERIC_OTA/sdkconfig.board
-)
diff --git a/ports/esp32/boards/GENERIC_OTA/mpconfigboard.h b/ports/esp32/boards/GENERIC_OTA/mpconfigboard.h
deleted file mode 100644
index ff39c4b2b7..0000000000
--- a/ports/esp32/boards/GENERIC_OTA/mpconfigboard.h
+++ /dev/null
@@ -1,2 +0,0 @@
-#define MICROPY_HW_BOARD_NAME "4MB/OTA module"
-#define MICROPY_HW_MCU_NAME "ESP32"
diff --git a/ports/esp32/boards/GENERIC_S2/mpconfigboard.h b/ports/esp32/boards/GENERIC_S2/mpconfigboard.h
deleted file mode 100644
index c4f86a8fc6..0000000000
--- a/ports/esp32/boards/GENERIC_S2/mpconfigboard.h
+++ /dev/null
@@ -1,8 +0,0 @@
-#define MICROPY_HW_BOARD_NAME               "ESP32S2 module"
-#define MICROPY_HW_MCU_NAME                 "ESP32S2"
-
-#define MICROPY_PY_BLUETOOTH                (0)
-#define MICROPY_HW_ENABLE_SDCARD            (0)
-
-// Enable UART REPL for modules that have an external USB-UART and don't use native USB.
-#define MICROPY_HW_ENABLE_UART_REPL         (1)
diff --git a/ports/esp32/boards/GENERIC_S3/mpconfigboard.cmake b/ports/esp32/boards/GENERIC_S3/mpconfigboard.cmake
deleted file mode 100644
index 3d83f89044..0000000000
--- a/ports/esp32/boards/GENERIC_S3/mpconfigboard.cmake
+++ /dev/null
@@ -1,8 +0,0 @@
-set(IDF_TARGET esp32s3)
-
-set(SDKCONFIG_DEFAULTS
-    boards/sdkconfig.base
-    boards/sdkconfig.usb
-    boards/sdkconfig.ble
-    boards/GENERIC_S3/sdkconfig.board
-)
diff --git a/ports/esp32/boards/GENERIC_S3/mpconfigboard.h b/ports/esp32/boards/GENERIC_S3/mpconfigboard.h
deleted file mode 100644
index b8f5fb2560..0000000000
--- a/ports/esp32/boards/GENERIC_S3/mpconfigboard.h
+++ /dev/null
@@ -1,10 +0,0 @@
-#define MICROPY_HW_BOARD_NAME               "ESP32S3 module"
-#define MICROPY_HW_MCU_NAME                 "ESP32S3"
-
-#define MICROPY_PY_MACHINE_DAC              (0)
-
-// Enable UART REPL for modules that have an external USB-UART and don't use native USB.
-#define MICROPY_HW_ENABLE_UART_REPL         (1)
-
-#define MICROPY_HW_I2C0_SCL                 (9)
-#define MICROPY_HW_I2C0_SDA                 (8)
diff --git a/ports/esp32/boards/GENERIC_S3/sdkconfig.board b/ports/esp32/boards/GENERIC_S3/sdkconfig.board
deleted file mode 100644
index a36b971162..0000000000
--- a/ports/esp32/boards/GENERIC_S3/sdkconfig.board
+++ /dev/null
@@ -1,9 +0,0 @@
-CONFIG_ESPTOOLPY_FLASHMODE_QIO=y
-CONFIG_ESPTOOLPY_FLASHFREQ_80M=y
-CONFIG_ESPTOOLPY_AFTER_NORESET=y
-
-CONFIG_ESPTOOLPY_FLASHSIZE_4MB=
-CONFIG_ESPTOOLPY_FLASHSIZE_8MB=y
-CONFIG_ESPTOOLPY_FLASHSIZE_16MB=
-CONFIG_PARTITION_TABLE_CUSTOM=y
-CONFIG_PARTITION_TABLE_CUSTOM_FILENAME="partitions-8MiB.csv"
diff --git a/ports/esp32/boards/GENERIC_S3_SPIRAM/board.json b/ports/esp32/boards/GENERIC_S3_SPIRAM/board.json
deleted file mode 100644
index 3b405d4a12..0000000000
--- a/ports/esp32/boards/GENERIC_S3_SPIRAM/board.json
+++ /dev/null
@@ -1,18 +0,0 @@
-{
-    "deploy": [
-        "../deploy_s3.md"
-    ],
-    "docs": "",
-    "features": [
-        "BLE",
-        "WiFi"
-    ],
-    "images": [
-        "generic_s3.jpg"
-    ],
-    "mcu": "esp32s3",
-    "product": "Generic ESP32-S3 (SPIRAM)",
-    "thumbnail": "",
-    "url": "https://www.espressif.com/en/products/modules",
-    "vendor": "Espressif"
-}
diff --git a/ports/esp32/boards/GENERIC_S3_SPIRAM/mpconfigboard.cmake b/ports/esp32/boards/GENERIC_S3_SPIRAM/mpconfigboard.cmake
deleted file mode 100644
index e0b92dcd26..0000000000
--- a/ports/esp32/boards/GENERIC_S3_SPIRAM/mpconfigboard.cmake
+++ /dev/null
@@ -1,9 +0,0 @@
-set(IDF_TARGET esp32s3)
-
-set(SDKCONFIG_DEFAULTS
-    boards/sdkconfig.base
-    boards/sdkconfig.usb
-    boards/sdkconfig.ble
-    boards/sdkconfig.spiram_sx
-    boards/GENERIC_S3_SPIRAM/sdkconfig.board
-)
diff --git a/ports/esp32/boards/GENERIC_S3_SPIRAM/sdkconfig.board b/ports/esp32/boards/GENERIC_S3_SPIRAM/sdkconfig.board
deleted file mode 100644
index a36b971162..0000000000
--- a/ports/esp32/boards/GENERIC_S3_SPIRAM/sdkconfig.board
+++ /dev/null
@@ -1,9 +0,0 @@
-CONFIG_ESPTOOLPY_FLASHMODE_QIO=y
-CONFIG_ESPTOOLPY_FLASHFREQ_80M=y
-CONFIG_ESPTOOLPY_AFTER_NORESET=y
-
-CONFIG_ESPTOOLPY_FLASHSIZE_4MB=
-CONFIG_ESPTOOLPY_FLASHSIZE_8MB=y
-CONFIG_ESPTOOLPY_FLASHSIZE_16MB=
-CONFIG_PARTITION_TABLE_CUSTOM=y
-CONFIG_PARTITION_TABLE_CUSTOM_FILENAME="partitions-8MiB.csv"
diff --git a/ports/esp32/boards/GENERIC_S3_SPIRAM_OCT/board.json b/ports/esp32/boards/GENERIC_S3_SPIRAM_OCT/board.json
deleted file mode 100644
index f3ca177ef9..0000000000
--- a/ports/esp32/boards/GENERIC_S3_SPIRAM_OCT/board.json
+++ /dev/null
@@ -1,18 +0,0 @@
-{
-    "deploy": [
-        "../deploy_s3.md"
-    ],
-    "docs": "",
-    "features": [
-        "BLE",
-        "WiFi"
-    ],
-    "images": [
-        "generic_s3.jpg"
-    ],
-    "mcu": "esp32s3",
-    "product": "Generic ESP32-S3 (SPIRAM Octal)",
-    "thumbnail": "",
-    "url": "https://www.espressif.com/en/products/modules",
-    "vendor": "Espressif"
-}
diff --git a/ports/esp32/boards/GENERIC_S3_SPIRAM_OCT/mpconfigboard.h b/ports/esp32/boards/GENERIC_S3_SPIRAM_OCT/mpconfigboard.h
deleted file mode 100644
index 88f6835c94..0000000000
--- a/ports/esp32/boards/GENERIC_S3_SPIRAM_OCT/mpconfigboard.h
+++ /dev/null
@@ -1,10 +0,0 @@
-#define MICROPY_HW_BOARD_NAME               "ESP32S3 module (spiram octal)"
-#define MICROPY_HW_MCU_NAME                 "ESP32S3"
-
-#define MICROPY_PY_MACHINE_DAC              (0)
-
-// Enable UART REPL for modules that have an external USB-UART and don't use native USB.
-#define MICROPY_HW_ENABLE_UART_REPL         (1)
-
-#define MICROPY_HW_I2C0_SCL                 (9)
-#define MICROPY_HW_I2C0_SDA                 (8)
diff --git a/ports/esp32/boards/GENERIC_SPIRAM/board.md b/ports/esp32/boards/GENERIC_SPIRAM/board.md
deleted file mode 100644
index c638f63dd3..0000000000
--- a/ports/esp32/boards/GENERIC_SPIRAM/board.md
+++ /dev/null
@@ -1 +0,0 @@
-The following files are firmware for ESP32-based boards with external SPIRAM (also known as PSRAM).
diff --git a/ports/esp32/boards/GENERIC_SPIRAM/mpconfigboard.cmake b/ports/esp32/boards/GENERIC_SPIRAM/mpconfigboard.cmake
deleted file mode 100644
index 2e1d799b93..0000000000
--- a/ports/esp32/boards/GENERIC_SPIRAM/mpconfigboard.cmake
+++ /dev/null
@@ -1,5 +0,0 @@
-set(SDKCONFIG_DEFAULTS
-    boards/sdkconfig.base
-    boards/sdkconfig.ble
-    boards/sdkconfig.spiram
-)
diff --git a/ports/esp32/boards/GENERIC_SPIRAM/mpconfigboard.h b/ports/esp32/boards/GENERIC_SPIRAM/mpconfigboard.h
deleted file mode 100644
index a5982e47e5..0000000000
--- a/ports/esp32/boards/GENERIC_SPIRAM/mpconfigboard.h
+++ /dev/null
@@ -1,2 +0,0 @@
-#define MICROPY_HW_BOARD_NAME "ESP32 module (spiram)"
-#define MICROPY_HW_MCU_NAME "ESP32"
diff --git a/ports/esp32/boards/GENERIC_UNICORE/board.json b/ports/esp32/boards/GENERIC_UNICORE/board.json
deleted file mode 100644
index 8fed71a018..0000000000
--- a/ports/esp32/boards/GENERIC_UNICORE/board.json
+++ /dev/null
@@ -1,19 +0,0 @@
-{
-    "deploy": [
-        "../deploy.md"
-    ],
-    "docs": "",
-    "features": [
-        "BLE",
-        "WiFi"
-    ],
-    "id": "esp32-unicore",
-    "images": [
-        "generic_unicore.jpg"
-    ],
-    "mcu": "esp32",
-    "product": "ESP32 Unicore",
-    "thumbnail": "",
-    "url": "https://www.espressif.com/en/products/modules",
-    "vendor": "Espressif"
-}
diff --git a/ports/esp32/boards/GENERIC_UNICORE/board.md b/ports/esp32/boards/GENERIC_UNICORE/board.md
deleted file mode 100644
index b41c167498..0000000000
--- a/ports/esp32/boards/GENERIC_UNICORE/board.md
+++ /dev/null
@@ -1 +0,0 @@
-The following files are daily firmware for single-core ESP32-based boards without external SPIRAM.
diff --git a/ports/esp32/boards/GENERIC_UNICORE/mpconfigboard.cmake b/ports/esp32/boards/GENERIC_UNICORE/mpconfigboard.cmake
deleted file mode 100644
index 2f34688c8c..0000000000
--- a/ports/esp32/boards/GENERIC_UNICORE/mpconfigboard.cmake
+++ /dev/null
@@ -1,5 +0,0 @@
-set(SDKCONFIG_DEFAULTS
-    boards/sdkconfig.base
-    boards/sdkconfig.ble
-    boards/GENERIC_UNICORE/sdkconfig.board
-)
diff --git a/ports/esp32/boards/GENERIC_UNICORE/mpconfigboard.h b/ports/esp32/boards/GENERIC_UNICORE/mpconfigboard.h
deleted file mode 100644
index 5d0624b9c3..0000000000
--- a/ports/esp32/boards/GENERIC_UNICORE/mpconfigboard.h
+++ /dev/null
@@ -1,2 +0,0 @@
-#define MICROPY_HW_BOARD_NAME "ESP32 Unicore module"
-#define MICROPY_HW_MCU_NAME "ESP32-UNICORE"
diff --git a/ports/esp32/boards/LILYGO_TTGO_LORA32/board.json b/ports/esp32/boards/LILYGO_TTGO_LORA32/board.json
index 9dd76b5792..525551df3b 100644
--- a/ports/esp32/boards/LILYGO_TTGO_LORA32/board.json
+++ b/ports/esp32/boards/LILYGO_TTGO_LORA32/board.json
@@ -5,10 +5,11 @@
     "docs": "",
     "features": [
         "BLE",
+        "Display",
+        "External Flash",
         "LoRa",
-        "OLED",
         "SDCard",
-        "USB-MICRO",
+        "USB",
         "WiFi"
     ],
     "images": [
diff --git a/ports/esp32/boards/LOLIN_C3_MINI/board.json b/ports/esp32/boards/LOLIN_C3_MINI/board.json
index f47c672fa4..c9b91641e5 100644
--- a/ports/esp32/boards/LOLIN_C3_MINI/board.json
+++ b/ports/esp32/boards/LOLIN_C3_MINI/board.json
@@ -5,6 +5,7 @@
     "docs": "",
     "features": [
         "BLE",
+        "External Flash",
         "USB-C",
         "WiFi"
     ],
diff --git a/ports/esp32/boards/LOLIN_S2_MINI/board.json b/ports/esp32/boards/LOLIN_S2_MINI/board.json
index 41e62a0228..a45d0434d9 100644
--- a/ports/esp32/boards/LOLIN_S2_MINI/board.json
+++ b/ports/esp32/boards/LOLIN_S2_MINI/board.json
@@ -4,7 +4,8 @@
     ],
     "docs": "",
     "features": [
-        "SPIRAM",
+        "External Flash",
+        "External RAM",
         "USB-C",
         "WiFi"
     ],
diff --git a/ports/esp32/boards/LOLIN_S2_MINI/sdkconfig.board b/ports/esp32/boards/LOLIN_S2_MINI/sdkconfig.board
index cbb3ad06d9..00ccc281ea 100644
--- a/ports/esp32/boards/LOLIN_S2_MINI/sdkconfig.board
+++ b/ports/esp32/boards/LOLIN_S2_MINI/sdkconfig.board
@@ -1,6 +1,5 @@
 CONFIG_ESPTOOLPY_FLASHMODE_QIO=y
 CONFIG_ESPTOOLPY_FLASHFREQ_80M=y
-CONFIG_USB_AND_UART=y
 # LWIP
 CONFIG_LWIP_LOCAL_HOSTNAME="LOLIN_S2_MINI"
 # end of LWIP
diff --git a/ports/esp32/boards/LOLIN_S2_PICO/board.json b/ports/esp32/boards/LOLIN_S2_PICO/board.json
index 43322b87b0..6c72e60f80 100644
--- a/ports/esp32/boards/LOLIN_S2_PICO/board.json
+++ b/ports/esp32/boards/LOLIN_S2_PICO/board.json
@@ -4,10 +4,10 @@
     ],
     "docs": "",
     "features": [
-        "Breadboard Friendly",
-        "OLED",
-        "SPIRAM",
-        "STEMMA QT/QWIIC",
+        "Display",
+        "External Flash",
+        "External RAM",
+        "JST-SH",
         "USB-C",
         "WiFi"
     ],
diff --git a/ports/esp32/boards/LOLIN_S2_PICO/sdkconfig.board b/ports/esp32/boards/LOLIN_S2_PICO/sdkconfig.board
index eadff2f1b9..a49f3936e7 100644
--- a/ports/esp32/boards/LOLIN_S2_PICO/sdkconfig.board
+++ b/ports/esp32/boards/LOLIN_S2_PICO/sdkconfig.board
@@ -1,6 +1,5 @@
 CONFIG_ESPTOOLPY_FLASHMODE_QIO=y
 CONFIG_ESPTOOLPY_FLASHFREQ_80M=y
-CONFIG_USB_AND_UART=y
 # LWIP
 CONFIG_LWIP_LOCAL_HOSTNAME="LOLIN_S2_PICO"
 # end of LWIP
diff --git a/ports/esp32/boards/M5STACK_ATOM/board.json b/ports/esp32/boards/M5STACK_ATOM/board.json
index 9d1886887c..4b6c09db3a 100644
--- a/ports/esp32/boards/M5STACK_ATOM/board.json
+++ b/ports/esp32/boards/M5STACK_ATOM/board.json
@@ -4,9 +4,9 @@
     ],
     "docs": "",
     "features": [
-        "Grove",
+        "External Flash",
         "IMU",
-        "Infrared",
+        "JST-PH",
         "RGB LED",
         "USB-C",
         "WiFi"
diff --git a/ports/esp32/boards/OLIMEX_ESP32_POE/board.json b/ports/esp32/boards/OLIMEX_ESP32_POE/board.json
index 84b6680d59..e62b960ccd 100644
--- a/ports/esp32/boards/OLIMEX_ESP32_POE/board.json
+++ b/ports/esp32/boards/OLIMEX_ESP32_POE/board.json
@@ -5,12 +5,12 @@
     "docs": "",
     "features": [
         "BLE",
-        "WiFi",
-        "MicroSD",
         "Battery Charging",
         "Ethernet",
+        "External Flash",
         "PoE",
-        "Breadboard friendly"
+        "WiFi",
+        "microSD"
     ],
     "images": [
         "ESP32-POE-ISO-1.jpg"
diff --git a/ports/esp32/boards/SIL_WESP32/board.json b/ports/esp32/boards/SIL_WESP32/board.json
index 050620d618..50dd2cc660 100644
--- a/ports/esp32/boards/SIL_WESP32/board.json
+++ b/ports/esp32/boards/SIL_WESP32/board.json
@@ -6,10 +6,10 @@
     "features": [
         "BLE",
         "Ethernet",
+        "External Flash",
         "PoE",
         "WiFi"
     ],
-    "id": "wesp32",
     "images": [
         "wesp32-iso.jpg",
         "wesp32-top.jpg"
@@ -18,5 +18,5 @@
     "product": "SIL WESP32",
     "thumbnail": "",
     "url": "https://wesp32.com/",
-    "vendor": "Silicognition LLC"
+    "vendor": "Silicognition"
 }
diff --git a/ports/esp32/boards/UM_FEATHERS2/board.json b/ports/esp32/boards/UM_FEATHERS2/board.json
index fa5b213db0..4de9a7d4f7 100644
--- a/ports/esp32/boards/UM_FEATHERS2/board.json
+++ b/ports/esp32/boards/UM_FEATHERS2/board.json
@@ -5,17 +5,17 @@
     "docs": "",
     "features": [
         "Battery Charging",
+        "External Flash",
+        "External RAM",
         "Feather",
+        "JST-SH",
         "RGB LED",
-        "SPIRAM",
-        "STEMMA QT/QWIIC",
         "USB-C",
         "WiFi"
     ],
     "features_non_filterable": [
         "Second LDO"
     ],
-    "id": "featherS2",
     "images": [
         "unexpectedmaker_feathers2.jpg"
     ],
diff --git a/ports/esp32/boards/UM_FEATHERS2/pins.csv b/ports/esp32/boards/UM_FEATHERS2/pins.csv
new file mode 100644
index 0000000000..edb7273f32
--- /dev/null
+++ b/ports/esp32/boards/UM_FEATHERS2/pins.csv
@@ -0,0 +1,12 @@
+AMB_LIGHT,GPIO4
+I2C_SCL,GPIO8
+I2C_SDA,GPIO9
+LDO2_PWR,GPIO21
+LED_BLUE,GPIO13
+RGB_DATA,GPIO40
+RGB_CLK,GPIO45
+SPI_MOSI,GPIO35
+SPI_SCK,GPIO36
+SPI_MISO,GPIO37
+UART0_TX,GPIO43
+UART0_RX,GPIO44
diff --git a/ports/esp32/boards/UM_FEATHERS2/sdkconfig.board b/ports/esp32/boards/UM_FEATHERS2/sdkconfig.board
index b23755dea7..c2e1c2b3d3 100644
--- a/ports/esp32/boards/UM_FEATHERS2/sdkconfig.board
+++ b/ports/esp32/boards/UM_FEATHERS2/sdkconfig.board
@@ -2,6 +2,8 @@ CONFIG_ESPTOOLPY_FLASHMODE_QIO=y
 CONFIG_ESPTOOLPY_FLASHFREQ_80M=y
 CONFIG_ESPTOOLPY_AFTER_NORESET=y
 
+CONFIG_SPIRAM_MEMTEST=
+
 CONFIG_ESPTOOLPY_FLASHSIZE_4MB=
 CONFIG_ESPTOOLPY_FLASHSIZE_16MB=y
 CONFIG_PARTITION_TABLE_CUSTOM=y
diff --git a/ports/esp32/boards/UM_FEATHERS2NEO/board.json b/ports/esp32/boards/UM_FEATHERS2NEO/board.json
index d809485e86..dfa1f46dc3 100644
--- a/ports/esp32/boards/UM_FEATHERS2NEO/board.json
+++ b/ports/esp32/boards/UM_FEATHERS2NEO/board.json
@@ -5,17 +5,17 @@
     "docs": "",
     "features": [
         "Battery Charging",
+        "External Flash",
+        "External RAM",
         "Feather",
+        "JST-SH",
         "RGB LED",
-        "SPIRAM",
-        "STEMMA QT/QWIIC",
         "USB-C",
         "WiFi"
     ],
     "features_non_filterable": [
         "5x5 RGB LED Matrix"
     ],
-    "id": "featherS2neo",
     "images": [
         "FeatherS2_Neo_White_Product2.jpg"
     ],
diff --git a/ports/esp32/boards/UM_FEATHERS2NEO/pins.csv b/ports/esp32/boards/UM_FEATHERS2NEO/pins.csv
new file mode 100644
index 0000000000..48e933dc95
--- /dev/null
+++ b/ports/esp32/boards/UM_FEATHERS2NEO/pins.csv
@@ -0,0 +1,14 @@
+I2C_SCL,GPIO8
+I2C_SDA,GPIO9
+LED_BLUE,GPIO13
+RGB_DATA,GPIO40
+RGB_PWR,GPIO39
+RGB_MATRIX_DATA,GPIO21
+RGB_MATRIX_DATA,GPIO4
+SPI_MOSI,GPIO35
+SPI_SCK,GPIO36
+SPI_MISO,GPIO37
+UART0_TX,GPIO43
+UART0_RX,GPIO44
+VBAT_SENSE,GPIO2
+VBUS_SENSE,GPIO34
diff --git a/ports/esp32/boards/UM_FEATHERS2NEO/sdkconfig.board b/ports/esp32/boards/UM_FEATHERS2NEO/sdkconfig.board
index b2c6979a70..a624f7fd97 100644
--- a/ports/esp32/boards/UM_FEATHERS2NEO/sdkconfig.board
+++ b/ports/esp32/boards/UM_FEATHERS2NEO/sdkconfig.board
@@ -1,6 +1,5 @@
 CONFIG_ESPTOOLPY_FLASHMODE_QIO=y
 CONFIG_ESPTOOLPY_FLASHFREQ_80M=y
-CONFIG_USB_AND_UART=y
 CONFIG_ESPTOOLPY_AFTER_NORESET=y
 
 # LWIP
diff --git a/ports/esp32/boards/UM_FEATHERS3/board.json b/ports/esp32/boards/UM_FEATHERS3/board.json
index 68423cca5e..235d52a12d 100644
--- a/ports/esp32/boards/UM_FEATHERS3/board.json
+++ b/ports/esp32/boards/UM_FEATHERS3/board.json
@@ -4,18 +4,17 @@
     ],
     "docs": "",
     "features": [
-        "Battery Charging",
-        "RGB LED",
-        "SPIRAM",
-        "USB-C",
-        "WiFi",
         "BLE",
-        "STEMMA QT/QWIIC",
-        "Feather"
+        "Battery Charging",
+        "External Flash",
+        "External RAM",
+        "Feather",
+        "JST-SH",
+        "RGB LED",
+        "USB-C",
+        "WiFi"
     ],
-    "features_non_filterable": [
-    ],
-    "id": "feathers3",
+    "features_non_filterable": [],
     "images": [
         "unexpectedmaker_feathers3.jpg"
     ],
diff --git a/ports/esp32/boards/UM_FEATHERS3/mpconfigboard.h b/ports/esp32/boards/UM_FEATHERS3/mpconfigboard.h
index 91ea5056d1..488a588442 100644
--- a/ports/esp32/boards/UM_FEATHERS3/mpconfigboard.h
+++ b/ports/esp32/boards/UM_FEATHERS3/mpconfigboard.h
@@ -7,6 +7,9 @@
 #define MICROPY_HW_I2C0_SCL                 (9)
 #define MICROPY_HW_I2C0_SDA                 (8)
 
+#define MICROPY_HW_I2C1_SCL                 (15)
+#define MICROPY_HW_I2C1_SDA                 (16)
+
 #define MICROPY_HW_SPI1_MOSI                (35)
 #define MICROPY_HW_SPI1_MISO                (37)
 #define MICROPY_HW_SPI1_SCK                 (36)
diff --git a/ports/esp32/boards/UM_FEATHERS3/pins.csv b/ports/esp32/boards/UM_FEATHERS3/pins.csv
new file mode 100644
index 0000000000..38240bc33e
--- /dev/null
+++ b/ports/esp32/boards/UM_FEATHERS3/pins.csv
@@ -0,0 +1,15 @@
+AMB_LIGHT,GPIO4
+I2C_SCL,GPIO9
+I2C_SDA,GPIO8
+I2C_SCL2,GPIO15
+I2C_SDA2,GPIO16
+LDO2_PWR,GPIO39
+LED_BLUE,GPIO13
+SPI_MOSI,GPIO35
+SPI_SCK,GPIO36
+SPI_MISO,GPIO37
+RGB_DATA,GPIO40
+UART0_TX,GPIO43
+UART0_RX,GPIO44
+VBAT_SENSE,GPIO2
+VBUS_SENSE,GPIO34
diff --git a/ports/esp32/boards/UM_FEATHERS3/sdkconfig.board b/ports/esp32/boards/UM_FEATHERS3/sdkconfig.board
index 804944ab24..3c8df5e2a8 100644
--- a/ports/esp32/boards/UM_FEATHERS3/sdkconfig.board
+++ b/ports/esp32/boards/UM_FEATHERS3/sdkconfig.board
@@ -5,6 +5,7 @@ CONFIG_ESPTOOLPY_AFTER_NORESET=y
 CONFIG_ESPTOOLPY_FLASHSIZE_4MB=
 CONFIG_ESPTOOLPY_FLASHSIZE_8MB=
 CONFIG_ESPTOOLPY_FLASHSIZE_16MB=y
+CONFIG_SPIRAM_MEMTEST=
 CONFIG_PARTITION_TABLE_CUSTOM=y
 CONFIG_PARTITION_TABLE_CUSTOM_FILENAME="partitions-16MiB.csv"
 
diff --git a/ports/esp32/boards/UM_NANOS3/board.json b/ports/esp32/boards/UM_NANOS3/board.json
new file mode 100644
index 0000000000..2eb40ac3c9
--- /dev/null
+++ b/ports/esp32/boards/UM_NANOS3/board.json
@@ -0,0 +1,25 @@
+{
+    "deploy": [
+        "deploy.md"
+    ],
+    "docs": "",
+    "features": [
+        "Battery Charging",
+        "RGB LED",
+        "SPIRAM",
+        "WiFi",
+        "BLE"
+    ],
+    "features_non_filterable": [
+        "TinyPICO Nano Compatible"
+    ],
+    "id": "nanos3",
+    "images": [
+        "unexpectedmaker_nanos3.jpg"
+    ],
+    "mcu": "esp32s3",
+    "product": "NanoS3",
+    "thumbnail": "",
+    "url": "https://nanos3.io",
+    "vendor": "Unexpected Maker"
+}
diff --git a/ports/esp32/boards/UM_NANOS3/board.md b/ports/esp32/boards/UM_NANOS3/board.md
new file mode 100644
index 0000000000..9cb5310f63
--- /dev/null
+++ b/ports/esp32/boards/UM_NANOS3/board.md
@@ -0,0 +1 @@
+The following files are firmware for the NanoS3.
diff --git a/ports/esp32/boards/UM_NANOS3/deploy.md b/ports/esp32/boards/UM_NANOS3/deploy.md
new file mode 100644
index 0000000000..725cff4946
--- /dev/null
+++ b/ports/esp32/boards/UM_NANOS3/deploy.md
@@ -0,0 +1,52 @@
+Program your board using the latest version of the esptool.py program, found [here](https://github.com/espressif/esptool).
+
+To flash or erase your NanoS3, you have to first put it into download mode.
+To do this, follow these steps:
+
+- Press and hold the [BOOT] button
+- Press and release the [RESET] button
+- Release the [BOOT] button
+
+Now the board is in download mode and the native USB will have enumerated as a serial device.
+
+If you are putting MicroPython on your board for the first time then you should
+first erase the entire flash using:
+
+### Linux
+```bash
+esptool.py --chip esp32s3 --port /dev/ttyACM0 erase_flash
+```
+
+### Mac
+Please do a `ls /dev/cu.usbm*` to determine the port your board has enumerated as.
+```bash
+esptool.py --chip esp32s3 --port /dev/cu.usbmodem01 erase_flash
+```
+
+### Windows
+Change (X) to whatever COM port is being used by the board
+```bash
+esptool --chip esp32s3 --port COM(X) erase_flash
+```
+
+Now download the version of the firmware you would like to install from the options below,
+then use the following command to program the firmware starting at address 0x0,
+remembering to replace `nanos3-micropython-firmware-version.bin` with the name of
+the firmware you just downloaded:
+
+### Linux
+```bash
+esptool.py --chip esp32s3 --port /dev/ttyACM0 write_flash -z 0x0 nanos3-micropython-firmware-version.bin
+```
+
+### Mac
+Please do a `ls /dev/cu.usbm*` to determine the port your board has enumerated as.
+```bash
+esptool.py --chip esp32s3 --port /dev/cu.usbmodem01 write_flash -z 0x0 nanos3-micropython-firmware-version.bin
+```
+
+### Windows
+Change (X) to whatever COM port is being used by the board
+```bash
+esptool --chip esp32s3 --port COM(X) write_flash -z 0x0 nanos3-micropython-firmware-version.bin
+```
diff --git a/ports/esp32/boards/UM_NANOS3/manifest.py b/ports/esp32/boards/UM_NANOS3/manifest.py
new file mode 100644
index 0000000000..7ae2ed15d9
--- /dev/null
+++ b/ports/esp32/boards/UM_NANOS3/manifest.py
@@ -0,0 +1,2 @@
+include("$(PORT_DIR)/boards/manifest.py")
+freeze("modules")
diff --git a/ports/esp32/boards/UM_NANOS3/modules/nanos3.py b/ports/esp32/boards/UM_NANOS3/modules/nanos3.py
new file mode 100644
index 0000000000..b3d57f121a
--- /dev/null
+++ b/ports/esp32/boards/UM_NANOS3/modules/nanos3.py
@@ -0,0 +1,46 @@
+# NanoS3 Helper Library
+# MIT license; Copyright (c) 2023 Seon Rozenblum - Unexpected Maker
+#
+# Project home:
+#   https://nanos3.io
+
+# Import required libraries
+from micropython import const
+from machine import Pin, ADC
+import time
+
+# TinyS3 Hardware Pin Assignments
+
+# RGB LED Pins
+RGB_DATA = const(41)
+RGB_PWR = const(42)
+
+# SPI
+SPI_MOSI = const(35)
+SPI_MISO = const(37)
+SPI_CLK = const(36)
+
+# I2C
+I2C_SDA = const(8)
+I2C_SCL = const(9)
+
+
+# Helper functions
+def set_pixel_power(state):
+    """Enable or Disable power to the onboard NeoPixel to either show colour, or to reduce power for deep sleep."""
+    Pin(RGB_PWR, Pin.OUT).value(state)
+
+
+# NeoPixel rainbow colour wheel
+def rgb_color_wheel(wheel_pos):
+    """Color wheel to allow for cycling through the rainbow of RGB colors."""
+    wheel_pos = wheel_pos % 255
+
+    if wheel_pos < 85:
+        return 255 - wheel_pos * 3, 0, wheel_pos * 3
+    elif wheel_pos < 170:
+        wheel_pos -= 85
+        return 0, wheel_pos * 3, 255 - wheel_pos * 3
+    else:
+        wheel_pos -= 170
+        return wheel_pos * 3, 255 - wheel_pos * 3, 0
diff --git a/ports/esp32/boards/GENERIC_S3_SPIRAM_OCT/mpconfigboard.cmake b/ports/esp32/boards/UM_NANOS3/mpconfigboard.cmake
similarity index 64%
rename from ports/esp32/boards/GENERIC_S3_SPIRAM_OCT/mpconfigboard.cmake
rename to ports/esp32/boards/UM_NANOS3/mpconfigboard.cmake
index 7a767c49d4..6c7f34009e 100644
--- a/ports/esp32/boards/GENERIC_S3_SPIRAM_OCT/mpconfigboard.cmake
+++ b/ports/esp32/boards/UM_NANOS3/mpconfigboard.cmake
@@ -6,6 +6,7 @@ set(SDKCONFIG_DEFAULTS
     boards/sdkconfig.ble
     boards/sdkconfig.240mhz
     boards/sdkconfig.spiram_sx
-    boards/sdkconfig.spiram_oct
-    boards/GENERIC_S3_SPIRAM_OCT/sdkconfig.board
+    boards/UM_TINYS3/sdkconfig.board
 )
+
+set(MICROPY_FROZEN_MANIFEST ${MICROPY_BOARD_DIR}/manifest.py)
diff --git a/ports/esp32/boards/UM_NANOS3/mpconfigboard.h b/ports/esp32/boards/UM_NANOS3/mpconfigboard.h
new file mode 100644
index 0000000000..1c2782bfb7
--- /dev/null
+++ b/ports/esp32/boards/UM_NANOS3/mpconfigboard.h
@@ -0,0 +1,12 @@
+#define MICROPY_HW_BOARD_NAME               "NanoS3"
+#define MICROPY_HW_MCU_NAME                 "ESP32-S3-FN8"
+#define MICROPY_PY_NETWORK_HOSTNAME_DEFAULT "NanoS3"
+
+#define MICROPY_PY_MACHINE_DAC              (0)
+
+#define MICROPY_HW_I2C0_SCL                 (9)
+#define MICROPY_HW_I2C0_SDA                 (8)
+
+#define MICROPY_HW_SPI1_MOSI                (35)
+#define MICROPY_HW_SPI1_MISO                (37)
+#define MICROPY_HW_SPI1_SCK                 (36)
diff --git a/ports/esp32/boards/UM_NANOS3/pins.csv b/ports/esp32/boards/UM_NANOS3/pins.csv
new file mode 100644
index 0000000000..44880f82ba
--- /dev/null
+++ b/ports/esp32/boards/UM_NANOS3/pins.csv
@@ -0,0 +1,10 @@
+I2C_SCL,GPIO8
+I2C_SDA,GPIO9
+SPI_SS,GPIO34
+SPI_MOSI,GPIO35
+SPI_SCK,GPIO36
+SPI_MISO,GPIO37
+RGB_DATA,GPIO41
+RGB_PWR,GPIO42
+UART0_TX,GPIO43
+UART0_RX,GPIO44
diff --git a/ports/esp32/boards/UM_NANOS3/sdkconfig.board b/ports/esp32/boards/UM_NANOS3/sdkconfig.board
new file mode 100644
index 0000000000..969bbc5be7
--- /dev/null
+++ b/ports/esp32/boards/UM_NANOS3/sdkconfig.board
@@ -0,0 +1,19 @@
+CONFIG_ESPTOOLPY_FLASHMODE_QIO=y
+CONFIG_ESPTOOLPY_FLASHFREQ_80M=y
+CONFIG_ESPTOOLPY_AFTER_NORESET=y
+
+CONFIG_ESPTOOLPY_FLASHSIZE_4MB=
+CONFIG_ESPTOOLPY_FLASHSIZE_8MB=y
+CONFIG_ESPTOOLPY_FLASHSIZE_16MB=
+CONFIG_SPIRAM_MEMTEST=
+CONFIG_PARTITION_TABLE_CUSTOM=y
+CONFIG_PARTITION_TABLE_CUSTOM_FILENAME="partitions-8MiB.csv"
+
+CONFIG_LWIP_LOCAL_HOSTNAME="UMNanoS3"
+
+CONFIG_TINYUSB_DESC_CUSTOM_VID=0x303A
+CONFIG_TINYUSB_DESC_CUSTOM_PID=0x817A
+CONFIG_TINYUSB_DESC_BCD_DEVICE=0x0100
+CONFIG_TINYUSB_DESC_MANUFACTURER_STRING="Unexpected Maker"
+CONFIG_TINYUSB_DESC_PRODUCT_STRING="NanoS3"
+CONFIG_TINYUSB_DESC_SERIAL_STRING="_ns3_"
diff --git a/ports/esp32/boards/UM_PROS3/board.json b/ports/esp32/boards/UM_PROS3/board.json
index 0122e4b991..8efc4e5ab5 100644
--- a/ports/esp32/boards/UM_PROS3/board.json
+++ b/ports/esp32/boards/UM_PROS3/board.json
@@ -4,18 +4,17 @@
     ],
     "docs": "",
     "features": [
-        "Battery Charging",
-        "RGB LED",
-        "SPIRAM",
-        "USB-C",
-        "WiFi",
         "BLE",
-        "STEMMA QT/QWIIC",
-        "Feather"
+        "Battery Charging",
+        "External Flash",
+        "External RAM",
+        "Feather",
+        "JST-SH",
+        "RGB LED",
+        "USB-C",
+        "WiFi"
     ],
-    "features_non_filterable": [
-    ],
-    "id": "pros3",
+    "features_non_filterable": [],
     "images": [
         "unexpectedmaker_pros3.jpg"
     ],
diff --git a/ports/esp32/boards/UM_PROS3/pins.csv b/ports/esp32/boards/UM_PROS3/pins.csv
new file mode 100644
index 0000000000..c0d4149d75
--- /dev/null
+++ b/ports/esp32/boards/UM_PROS3/pins.csv
@@ -0,0 +1,12 @@
+I2C_SCL,GPIO8
+I2C_SDA,GPIO9
+VBAT_SENSE,GPIO10
+LDO2_PWR,GPIO17
+RGB_DATA,GPIO18
+VBUS_SENSE,GPIO33
+SPI_SS,GPIO34
+SPI_MOSI,GPIO35
+SPI_SCK,GPIO36
+SPI_MISO,GPIO37
+UART0_TX,GPIO43
+UART0_RX,GPIO44
diff --git a/ports/esp32/boards/UM_PROS3/sdkconfig.board b/ports/esp32/boards/UM_PROS3/sdkconfig.board
index 71511e3c52..5d1ac0f684 100644
--- a/ports/esp32/boards/UM_PROS3/sdkconfig.board
+++ b/ports/esp32/boards/UM_PROS3/sdkconfig.board
@@ -5,6 +5,7 @@ CONFIG_ESPTOOLPY_AFTER_NORESET=y
 CONFIG_ESPTOOLPY_FLASHSIZE_4MB=
 CONFIG_ESPTOOLPY_FLASHSIZE_8MB=
 CONFIG_ESPTOOLPY_FLASHSIZE_16MB=y
+CONFIG_SPIRAM_MEMTEST=
 CONFIG_PARTITION_TABLE_CUSTOM=y
 CONFIG_PARTITION_TABLE_CUSTOM_FILENAME="partitions-16MiB.csv"
 
diff --git a/ports/esp32/boards/UM_TINYPICO/board.json b/ports/esp32/boards/UM_TINYPICO/board.json
index 9f1783a9f1..bf0b3d2c8c 100644
--- a/ports/esp32/boards/UM_TINYPICO/board.json
+++ b/ports/esp32/boards/UM_TINYPICO/board.json
@@ -4,17 +4,17 @@
     ],
     "docs": "",
     "features": [
-        "Battery Charging",
         "BLE",
+        "Battery Charging",
+        "External Flash",
+        "External RAM",
         "RGB LED",
-        "SPIRAM",
         "USB-C",
         "WiFi"
     ],
     "features_non_filterable": [
         "TinyPICO Compatible"
     ],
-    "id": "tinypico",
     "images": [
         "tinypico-v2-both.jpg"
     ],
@@ -23,7 +23,7 @@
     "thumbnail": "",
     "url": "https://www.tinypico.com/",
     "variants": {
-        "idf3": "Compiled with IDF 3.x"
+        "IDF3": "Compiled with IDF 3.x"
     },
     "vendor": "Unexpected Maker"
 }
diff --git a/ports/esp32/boards/UM_TINYPICO/pins.csv b/ports/esp32/boards/UM_TINYPICO/pins.csv
new file mode 100644
index 0000000000..a8ab074cce
--- /dev/null
+++ b/ports/esp32/boards/UM_TINYPICO/pins.csv
@@ -0,0 +1,12 @@
+I2C_SCL,GPIO22
+I2C_SDA,GPIO21
+RGB_DATA,GPIO2
+RGB_CLK,GPIO12
+RGB_PWR,GPIO13
+SPI_SS,GPIO5
+SPI_MOSI,GPIO23
+SPI_SCK,GPIO18
+SPI_MISO,GPIO19
+VBAT_SENSE,GPIO35
+VBAT_CHRG,GPIO34
+VBUS_SENSE,GPIO9
diff --git a/ports/esp32/boards/UM_TINYS2/board.json b/ports/esp32/boards/UM_TINYS2/board.json
index e7068170cb..1b4c934dfa 100644
--- a/ports/esp32/boards/UM_TINYS2/board.json
+++ b/ports/esp32/boards/UM_TINYS2/board.json
@@ -5,16 +5,16 @@
     "docs": "",
     "features": [
         "Battery Charging",
+        "External Flash",
+        "External RAM",
+        "JST-SH",
         "RGB LED",
-        "SPIRAM",
-        "STEMMA QT/QWIIC",
         "USB-C",
         "WiFi"
     ],
     "features_non_filterable": [
         "TinyPICO Compatible"
     ],
-    "id": "tinys2",
     "images": [
         "TinyS2+Product+Shot.jpg"
     ],
diff --git a/ports/esp32/boards/UM_TINYS2/pins.csv b/ports/esp32/boards/UM_TINYS2/pins.csv
new file mode 100644
index 0000000000..1ef7b2ecc8
--- /dev/null
+++ b/ports/esp32/boards/UM_TINYS2/pins.csv
@@ -0,0 +1,12 @@
+I2C_SCL,GPIO8
+I2C_SDA,GPIO9
+RGB_DATA,GPIO1
+RGB_PWR,GPIO2
+SPI_SS,GPIO14
+SPI_MOSI,GPIO35
+SPI_SCK,GPIO36
+SPI_MISO,GPIO37
+UART0_TX,GPIO43
+UART0_RX,GPIO44
+VBAT_SENSE,GPIO3
+VBUS_SENSE,GPIO21
diff --git a/ports/esp32/boards/UM_TINYS2/sdkconfig.board b/ports/esp32/boards/UM_TINYS2/sdkconfig.board
index 09e0deb078..0a2097e242 100644
--- a/ports/esp32/boards/UM_TINYS2/sdkconfig.board
+++ b/ports/esp32/boards/UM_TINYS2/sdkconfig.board
@@ -1,6 +1,5 @@
 CONFIG_ESPTOOLPY_FLASHMODE_QIO=y
 CONFIG_ESPTOOLPY_FLASHFREQ_80M=y
-CONFIG_USB_AND_UART=y
 CONFIG_ESPTOOLPY_AFTER_NORESET=y
 
 # LWIP
diff --git a/ports/esp32/boards/UM_TINYS3/board.json b/ports/esp32/boards/UM_TINYS3/board.json
index 73482a6284..27ae46a249 100644
--- a/ports/esp32/boards/UM_TINYS3/board.json
+++ b/ports/esp32/boards/UM_TINYS3/board.json
@@ -4,17 +4,17 @@
     ],
     "docs": "",
     "features": [
+        "BLE",
         "Battery Charging",
+        "External Flash",
+        "External RAM",
         "RGB LED",
-        "SPIRAM",
         "USB-C",
-        "WiFi",
-        "BLE"
+        "WiFi"
     ],
     "features_non_filterable": [
         "TinyPICO Compatible"
     ],
-    "id": "tinys3",
     "images": [
         "unexpectedmaker_tinys3.jpg"
     ],
diff --git a/ports/esp32/boards/UM_TINYS3/pins.csv b/ports/esp32/boards/UM_TINYS3/pins.csv
new file mode 100644
index 0000000000..1fad949a44
--- /dev/null
+++ b/ports/esp32/boards/UM_TINYS3/pins.csv
@@ -0,0 +1,12 @@
+I2C_SCL,GPIO8
+I2C_SDA,GPIO9
+RGB_DATA,GPIO18
+RGB_PWR,GPIO19
+SPI_SS,GPIO34
+SPI_MOSI,GPIO35
+SPI_SCK,GPIO36
+SPI_MISO,GPIO37
+UART0_TX,GPIO43
+UART0_RX,GPIO44
+VBAT_SENSE,GPIO10
+VBUS_SENSE,GPIO33
diff --git a/ports/esp32/boards/UM_TINYS3/sdkconfig.board b/ports/esp32/boards/UM_TINYS3/sdkconfig.board
index c22e78eaea..7b913a565f 100644
--- a/ports/esp32/boards/UM_TINYS3/sdkconfig.board
+++ b/ports/esp32/boards/UM_TINYS3/sdkconfig.board
@@ -5,6 +5,7 @@ CONFIG_ESPTOOLPY_AFTER_NORESET=y
 CONFIG_ESPTOOLPY_FLASHSIZE_4MB=
 CONFIG_ESPTOOLPY_FLASHSIZE_8MB=y
 CONFIG_ESPTOOLPY_FLASHSIZE_16MB=
+CONFIG_SPIRAM_MEMTEST=
 CONFIG_PARTITION_TABLE_CUSTOM=y
 CONFIG_PARTITION_TABLE_CUSTOM_FILENAME="partitions-8MiB.csv"
 
diff --git a/ports/esp32/boards/sdkconfig.base b/ports/esp32/boards/sdkconfig.base
index bf6c3f45c5..4b7c852332 100644
--- a/ports/esp32/boards/sdkconfig.base
+++ b/ports/esp32/boards/sdkconfig.base
@@ -13,6 +13,7 @@ CONFIG_APP_EXCLUDE_PROJECT_NAME_VAR=y
 
 # Bootloader config
 CONFIG_BOOTLOADER_LOG_LEVEL_WARN=y
+CONFIG_BOOTLOADER_SKIP_VALIDATE_IN_DEEP_SLEEP=y
 
 # Change default log level to "ERROR" (instead of "INFO")
 CONFIG_LOG_DEFAULT_LEVEL_INFO=n
@@ -49,6 +50,15 @@ CONFIG_LWIP_PPP_CHAP_SUPPORT=y
 # Use 4kiB output buffer instead of default 16kiB
 CONFIG_MBEDTLS_ASYMMETRIC_CONTENT_LEN=y
 
+# Allow mbedTLS to allocate from PSRAM or internal memory
+#
+# (The ESP-IDF default is internal-only, partly for physical security to prevent
+# possible information leakage from unencrypted PSRAM contents on the original
+# ESP32 - no PSRAM encryption on that chip. MicroPython doesn't support flash
+# encryption and is already storing the Python heap in PSRAM so this isn't a
+# significant factor in overall physical security.)
+CONFIG_MBEDTLS_DEFAULT_MEM_ALLOC=y
+
 # ULP coprocessor support
 # Only on: ESP32, ESP32S2, ESP32S3
 CONFIG_ULP_COPROC_ENABLED=y
@@ -58,7 +68,7 @@ CONFIG_ULP_COPROC_RESERVE_MEM=2040
 # For cmake build
 CONFIG_ESPTOOLPY_FLASHSIZE_4MB=y
 CONFIG_PARTITION_TABLE_CUSTOM=y
-CONFIG_PARTITION_TABLE_CUSTOM_FILENAME="partitions.csv"
+CONFIG_PARTITION_TABLE_CUSTOM_FILENAME="partitions-4MiB.csv"
 
 # To reduce iRAM usage
 CONFIG_ESP32_WIFI_IRAM_OPT=n
diff --git a/ports/esp32/boards/sdkconfig.spiram b/ports/esp32/boards/sdkconfig.spiram
index 74d35f7b4a..4dfc63624b 100644
--- a/ports/esp32/boards/sdkconfig.spiram
+++ b/ports/esp32/boards/sdkconfig.spiram
@@ -3,7 +3,11 @@
 CONFIG_SPIRAM=y
 CONFIG_SPIRAM_CACHE_WORKAROUND=y
 CONFIG_SPIRAM_IGNORE_NOTFOUND=y
-CONFIG_SPIRAM_USE_CAPS_ALLOC=y
+CONFIG_SPIRAM_USE_MALLOC=y
+
+# This is the threshold for preferring small allocations from internal memory
+# first, before failing over to PSRAM.
+CONFIG_SPIRAM_MALLOC_ALWAYSINTERNAL=8192
 
 # SPIRAM increases the size of the firmware and overflows iram0_0_seg, due
 # to PSRAM bug workarounds.  Apply some options to reduce the firmware size.
diff --git a/ports/esp32/boards/sdkconfig.spiram_sx b/ports/esp32/boards/sdkconfig.spiram_sx
index 329a507337..efe53ada41 100644
--- a/ports/esp32/boards/sdkconfig.spiram_sx
+++ b/ports/esp32/boards/sdkconfig.spiram_sx
@@ -7,4 +7,8 @@ CONFIG_SPIRAM_SPEED_80M=y
 CONFIG_SPIRAM=y
 CONFIG_SPIRAM_BOOT_INIT=y
 CONFIG_SPIRAM_IGNORE_NOTFOUND=y
-CONFIG_SPIRAM_USE_CAPS_ALLOC=y
+CONFIG_SPIRAM_USE_MALLOC=y
+
+# This is the threshold for preferring small allocations from internal memory
+# first, before failing over to PSRAM.
+CONFIG_SPIRAM_MALLOC_ALWAYSINTERNAL=8192
diff --git a/ports/esp32/esp32_common.cmake b/ports/esp32/esp32_common.cmake
index 37a19316b6..f5219048f3 100644
--- a/ports/esp32/esp32_common.cmake
+++ b/ports/esp32/esp32_common.cmake
@@ -11,6 +11,9 @@ endif()
 # Include core source components.
 include(${MICROPY_DIR}/py/py.cmake)
 
+# CMAKE_BUILD_EARLY_EXPANSION is set during the component-discovery phase of
+# `idf.py build`, so none of the extmod/usermod (and in reality, most of the
+# micropython) rules need to happen. Specifically, you cannot invoke add_library.
 if(NOT CMAKE_BUILD_EARLY_EXPANSION)
     # Enable extmod components that will be configured by extmod.cmake.
     # A board may also have enabled additional components.
@@ -167,6 +170,7 @@ set(MICROPY_CROSS_FLAGS -march=xtensawin)
 # Set compile options for this port.
 target_compile_definitions(${MICROPY_TARGET} PUBLIC
     ${MICROPY_DEF_CORE}
+    ${MICROPY_DEF_BOARD}
     MICROPY_ESP_IDF_4=1
     MICROPY_VFS_FAT=1
     MICROPY_VFS_LFS2=1
diff --git a/ports/esp32/gccollect.c b/ports/esp32/gccollect.c
index 6fa287de28..4b6dd8ab61 100644
--- a/ports/esp32/gccollect.c
+++ b/ports/esp32/gccollect.c
@@ -39,30 +39,25 @@
 
 #include "xtensa/hal.h"
 
-static void gc_collect_inner(int level) {
+// The level argument must be volatile to force the compiler to emit code that
+// will call this function recursively, to nest the C stack.
+static void gc_collect_inner(volatile unsigned int level) {
     if (level < XCHAL_NUM_AREGS / 8) {
+        // Go deeper on the stack to spill more registers from the register window.
         gc_collect_inner(level + 1);
-        if (level != 0) {
-            return;
-        }
-    }
-
-    if (level == XCHAL_NUM_AREGS / 8) {
-        // get the sp
+    } else {
+        // Deep enough so that all registers are on the C stack, now trace the stack.
         volatile uint32_t sp = (uint32_t)esp_cpu_get_sp();
         gc_collect_root((void **)sp, ((mp_uint_t)MP_STATE_THREAD(stack_top) - sp) / sizeof(uint32_t));
-        return;
     }
-
-    // trace root pointers from any threads
-    #if MICROPY_PY_THREAD
-    mp_thread_gc_others();
-    #endif
 }
 
 void gc_collect(void) {
     gc_collect_start();
     gc_collect_inner(0);
+    #if MICROPY_PY_THREAD
+    mp_thread_gc_others();
+    #endif
     gc_collect_end();
 }
 
@@ -80,3 +75,13 @@ void gc_collect(void) {
 }
 
 #endif
+
+#if MICROPY_GC_SPLIT_HEAP_AUTO
+
+// The largest new region that is available to become Python heap is the largest
+// free block in the ESP-IDF system heap.
+size_t gc_get_max_new_split(void) {
+    return heap_caps_get_largest_free_block(MALLOC_CAP_DEFAULT);
+}
+
+#endif
diff --git a/ports/esp32/machine_uart.c b/ports/esp32/machine_uart.c
index e7b2b8376b..0b4f5890ba 100644
--- a/ports/esp32/machine_uart.c
+++ b/ports/esp32/machine_uart.c
@@ -153,9 +153,11 @@ STATIC void machine_uart_init_helper(machine_uart_obj_t *self, size_t n_args, co
 
     if (args[ARG_txbuf].u_int >= 0 || args[ARG_rxbuf].u_int >= 0) {
         // must reinitialise driver to change the tx/rx buffer size
+        #if MICROPY_HW_ENABLE_UART_REPL
         if (self->uart_num == MICROPY_HW_UART_REPL) {
             mp_raise_ValueError(MP_ERROR_TEXT("UART buffer size is fixed"));
         }
+        #endif
 
         if (args[ARG_txbuf].u_int >= 0) {
             self->txbuf = args[ARG_txbuf].u_int;
@@ -353,8 +355,11 @@ STATIC mp_obj_t machine_uart_make_new(const mp_obj_type_t *type, size_t n_args,
         #endif
     }
 
+    #if MICROPY_HW_ENABLE_UART_REPL
     // Only reset the driver if it's not the REPL UART.
-    if (uart_num != MICROPY_HW_UART_REPL) {
+    if (uart_num != MICROPY_HW_UART_REPL)
+    #endif
+    {
         // Remove any existing configuration
         uart_driver_delete(self->uart_num);
 
@@ -467,8 +472,17 @@ STATIC mp_uint_t machine_uart_read(mp_obj_t self_in, void *buf_in, mp_uint_t siz
         time_to_wait = pdMS_TO_TICKS(self->timeout);
     }
 
+    bool release_gil = time_to_wait > 0;
+    if (release_gil) {
+        MP_THREAD_GIL_EXIT();
+    }
+
     int bytes_read = uart_read_bytes(self->uart_num, buf_in, size, time_to_wait);
 
+    if (release_gil) {
+        MP_THREAD_GIL_ENTER();
+    }
+
     if (bytes_read <= 0) {
         *errcode = MP_EAGAIN;
         return MP_STREAM_ERROR;
diff --git a/ports/esp32/main.c b/ports/esp32/main.c
index 3a172e6f8d..1420dd579c 100644
--- a/ports/esp32/main.c
+++ b/ports/esp32/main.c
@@ -75,6 +75,10 @@
 #define MP_TASK_STACK_LIMIT_MARGIN (1024)
 #endif
 
+// Initial Python heap size. This starts small but adds new heap areas on
+// demand due to settings MICROPY_GC_SPLIT_HEAP & MICROPY_GC_SPLIT_HEAP_AUTO
+#define MP_TASK_HEAP_SIZE (64 * 1024)
+
 int vprintf_null(const char *format, va_list ap) {
     // do nothing: this is used as a log target during raw repl mode
     return 0;
@@ -85,10 +89,10 @@ void mp_task(void *pvParameter) {
     #if MICROPY_PY_THREAD
     mp_thread_init(pxTaskGetStackStart(NULL), MP_TASK_STACK_SIZE / sizeof(uintptr_t));
     #endif
-    #if CONFIG_USB_OTG_SUPPORTED
-    usb_init();
-    #elif CONFIG_ESP_CONSOLE_USB_SERIAL_JTAG
+    #if CONFIG_ESP_CONSOLE_USB_SERIAL_JTAG
     usb_serial_jtag_init();
+    #elif CONFIG_USB_OTG_SUPPORTED
+    usb_init();
     #endif
     #if MICROPY_HW_ENABLE_UART_REPL
     uart_stdout_init();
@@ -100,19 +104,13 @@ void mp_task(void *pvParameter) {
         ESP_LOGE("esp_init", "can't create event loop: 0x%x\n", err);
     }
 
-    // Allocate the uPy heap using malloc and get the largest available region,
-    // limiting to 1/2 total available memory to leave memory for the OS.
-    // When SPIRAM is enabled, this will allocate from SPIRAM.
-    uint32_t caps = MALLOC_CAP_8BIT;
-    size_t heap_total = heap_caps_get_total_size(caps);
-    size_t mp_task_heap_size = MIN(heap_caps_get_largest_free_block(caps), heap_total / 2);
-    void *mp_task_heap = heap_caps_malloc(mp_task_heap_size, caps);
+    void *mp_task_heap = MP_PLAT_ALLOC_HEAP(MP_TASK_HEAP_SIZE);
 
 soft_reset:
     // initialise the stack pointer for the main thread
     mp_stack_set_top((void *)sp);
     mp_stack_set_limit(MP_TASK_STACK_SIZE - MP_TASK_STACK_LIMIT_MARGIN);
-    gc_init(mp_task_heap, mp_task_heap + mp_task_heap_size);
+    gc_init(mp_task_heap, mp_task_heap + MP_TASK_HEAP_SIZE);
     mp_init();
     mp_obj_list_append(mp_sys_path, MP_OBJ_NEW_QSTR(MP_QSTR__slash_lib));
     readline_init0();
diff --git a/ports/esp32/modnetwork.h b/ports/esp32/modnetwork.h
index 79bf9973ca..e57b80657f 100644
--- a/ports/esp32/modnetwork.h
+++ b/ports/esp32/modnetwork.h
@@ -57,6 +57,8 @@ MP_DECLARE_CONST_FUN_OBJ_VAR_BETWEEN(esp_network_ifconfig_obj);
 MP_DECLARE_CONST_FUN_OBJ_KW(esp_network_config_obj);
 MP_DECLARE_CONST_FUN_OBJ_VAR_BETWEEN(esp_network_phy_mode_obj);
 
+mp_obj_t esp_ifname(esp_netif_t *netif);
+
 NORETURN void esp_exceptions_helper(esp_err_t e);
 
 static inline void esp_exceptions(esp_err_t e) {
diff --git a/ports/esp32/modsocket.c b/ports/esp32/modsocket.c
index ba1fe096f6..fe76b5f760 100644
--- a/ports/esp32/modsocket.c
+++ b/ports/esp32/modsocket.c
@@ -386,7 +386,8 @@ STATIC mp_obj_t socket_setsockopt(size_t n_args, const mp_obj_t *args) {
 
     switch (opt) {
         // level: SOL_SOCKET
-        case SO_REUSEADDR: {
+        case SO_REUSEADDR:
+        case SO_BROADCAST: {
             int val = mp_obj_get_int(args[3]);
             int ret = lwip_setsockopt(self->fd, SOL_SOCKET, opt, &val, sizeof(int));
             if (ret != 0) {
@@ -395,6 +396,18 @@ STATIC mp_obj_t socket_setsockopt(size_t n_args, const mp_obj_t *args) {
             break;
         }
 
+        case SO_BINDTODEVICE: {
+            size_t len;
+            const char *val = mp_obj_str_get_data(args[3], &len);
+            char ifname[NETIF_NAMESIZE] = {0};
+            memcpy(&ifname, val, len);
+            int ret = lwip_setsockopt(self->fd, SOL_SOCKET, opt, &ifname, NETIF_NAMESIZE);
+            if (ret != 0) {
+                mp_raise_OSError(errno);
+            }
+            break;
+        }
+
             #if MICROPY_PY_SOCKET_EVENTS
         // level: SOL_SOCKET
         // special "register callback" option
@@ -858,6 +871,8 @@ STATIC const mp_rom_map_elem_t mp_module_socket_globals_table[] = {
     { MP_ROM_QSTR(MP_QSTR_IPPROTO_IP), MP_ROM_INT(IPPROTO_IP) },
     { MP_ROM_QSTR(MP_QSTR_SOL_SOCKET), MP_ROM_INT(SOL_SOCKET) },
     { MP_ROM_QSTR(MP_QSTR_SO_REUSEADDR), MP_ROM_INT(SO_REUSEADDR) },
+    { MP_ROM_QSTR(MP_QSTR_SO_BROADCAST), MP_ROM_INT(SO_BROADCAST) },
+    { MP_ROM_QSTR(MP_QSTR_SO_BINDTODEVICE), MP_ROM_INT(SO_BINDTODEVICE) },
     { MP_ROM_QSTR(MP_QSTR_IP_ADD_MEMBERSHIP), MP_ROM_INT(IP_ADD_MEMBERSHIP) },
 };
 
diff --git a/ports/esp32/mpconfigport.h b/ports/esp32/mpconfigport.h
index aa13eaf2fe..ae73e02e41 100644
--- a/ports/esp32/mpconfigport.h
+++ b/ports/esp32/mpconfigport.h
@@ -68,6 +68,9 @@
 #define MICROPY_PY_THREAD_GIL               (1)
 #define MICROPY_PY_THREAD_GIL_VM_DIVISOR    (32)
 
+#define MICROPY_GC_SPLIT_HEAP               (1)
+#define MICROPY_GC_SPLIT_HEAP_AUTO          (1)
+
 // extended modules
 #ifndef MICROPY_ESPNOW
 #define MICROPY_ESPNOW                      (1)
@@ -136,7 +139,6 @@
 #define MICROPY_HW_SOFTSPI_MAX_BAUDRATE     (esp_rom_get_cpu_ticks_per_us() * 1000000 / 200) // roughly
 #define MICROPY_PY_SSL                      (1)
 #define MICROPY_SSL_MBEDTLS                 (1)
-#define MICROPY_PY_SSL_FINALISER            (1)
 #define MICROPY_PY_WEBSOCKET                (1)
 #define MICROPY_PY_WEBREPL                  (1)
 #define MICROPY_PY_ONEWIRE                  (1)
diff --git a/ports/esp32/mphalport.c b/ports/esp32/mphalport.c
index 63a674c24b..d7003a1437 100644
--- a/ports/esp32/mphalport.c
+++ b/ports/esp32/mphalport.c
@@ -111,10 +111,10 @@ void mp_hal_stdout_tx_strn(const char *str, size_t len) {
     if (release_gil) {
         MP_THREAD_GIL_EXIT();
     }
-    #if CONFIG_USB_OTG_SUPPORTED
-    usb_tx_strn(str, len);
-    #elif CONFIG_ESP_CONSOLE_USB_SERIAL_JTAG
+    #if CONFIG_ESP_CONSOLE_USB_SERIAL_JTAG
     usb_serial_jtag_tx_strn(str, len);
+    #elif CONFIG_USB_OTG_SUPPORTED
+    usb_tx_strn(str, len);
     #endif
     #if MICROPY_HW_ENABLE_UART_REPL
     uart_stdout_tx_strn(str, len);
diff --git a/ports/esp32/mpthreadport.c b/ports/esp32/mpthreadport.c
index e6c7e9bc80..74dbc14797 100644
--- a/ports/esp32/mpthreadport.c
+++ b/ports/esp32/mpthreadport.c
@@ -98,6 +98,10 @@ void mp_thread_set_state(mp_state_thread_t *state) {
     vTaskSetThreadLocalStoragePointer(NULL, 1, state);
 }
 
+mp_uint_t mp_thread_get_id(void) {
+    return (mp_uint_t)xTaskGetCurrentTaskHandle();
+}
+
 void mp_thread_start(void) {
     mp_thread_mutex_lock(&thread_mutex, 1);
     for (mp_thread_t *th = thread; th != NULL; th = th->next) {
@@ -120,7 +124,7 @@ STATIC void freertos_entry(void *arg) {
     }
 }
 
-void mp_thread_create_ex(void *(*entry)(void *), void *arg, size_t *stack_size, int priority, char *name) {
+mp_uint_t mp_thread_create_ex(void *(*entry)(void *), void *arg, size_t *stack_size, int priority, char *name) {
     // store thread entry function into a global variable so we can access it
     ext_thread_entry = entry;
 
@@ -154,10 +158,12 @@ void mp_thread_create_ex(void *(*entry)(void *), void *arg, size_t *stack_size,
     *stack_size -= 1024;
 
     mp_thread_mutex_unlock(&thread_mutex);
+
+    return (mp_uint_t)th->id;
 }
 
-void mp_thread_create(void *(*entry)(void *), void *arg, size_t *stack_size) {
-    mp_thread_create_ex(entry, arg, stack_size, MP_THREAD_PRIORITY, "mp_thread");
+mp_uint_t mp_thread_create(void *(*entry)(void *), void *arg, size_t *stack_size) {
+    return mp_thread_create_ex(entry, arg, stack_size, MP_THREAD_PRIORITY, "mp_thread");
 }
 
 void mp_thread_finish(void) {
diff --git a/ports/esp32/network_common.c b/ports/esp32/network_common.c
index 082943e2ae..ca07f3c06b 100644
--- a/ports/esp32/network_common.c
+++ b/ports/esp32/network_common.c
@@ -41,6 +41,7 @@
 #include "esp_log.h"
 #include "esp_netif.h"
 #include "esp_wifi.h"
+#include "lwip/sockets.h"
 // #include "lwip/dns.h"
 
 NORETURN void esp_exceptions_helper(esp_err_t e) {
@@ -153,6 +154,15 @@ STATIC mp_obj_t esp_ifconfig(size_t n_args, const mp_obj_t *args) {
 }
 MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(esp_network_ifconfig_obj, 1, 2, esp_ifconfig);
 
+mp_obj_t esp_ifname(esp_netif_t *netif) {
+    char ifname[NETIF_NAMESIZE + 1] = {0};
+    mp_obj_t ret = mp_const_none;
+    if (esp_netif_get_netif_impl_name(netif, ifname) == ESP_OK && ifname[0] != 0) {
+        ret = mp_obj_new_str((char *)ifname, strlen(ifname));
+    }
+    return ret;
+}
+
 STATIC mp_obj_t esp_phy_mode(size_t n_args, const mp_obj_t *args) {
     return mp_const_none;
 }
diff --git a/ports/esp32/network_lan.c b/ports/esp32/network_lan.c
index fe3ff6f772..8557700446 100644
--- a/ports/esp32/network_lan.c
+++ b/ports/esp32/network_lan.c
@@ -393,6 +393,10 @@ STATIC mp_obj_t lan_config(size_t n_args, const mp_obj_t *args, mp_map_t *kwargs
             esp_eth_ioctl(self->eth_handle, ETH_CMD_G_MAC_ADDR, mac);
             return mp_obj_new_bytes(mac, sizeof(mac));
         }
+        case MP_QSTR_ifname: {
+            val = esp_ifname(self->base.netif);
+            break;
+        }
         default:
             mp_raise_ValueError(MP_ERROR_TEXT("unknown config param"));
     }
diff --git a/ports/esp32/network_ppp.c b/ports/esp32/network_ppp.c
index caad7eb48b..ea0dd1706e 100644
--- a/ports/esp32/network_ppp.c
+++ b/ports/esp32/network_ppp.c
@@ -114,6 +114,8 @@ static void pppos_client_task(void *self_in) {
 
     self->client_task_handle = NULL;
     vTaskDelete(NULL);
+    for (;;) {
+    }
 }
 
 STATIC mp_obj_t ppp_active(size_t n_args, const mp_obj_t *args) {
@@ -266,11 +268,56 @@ STATIC mp_obj_t ppp_isconnected(mp_obj_t self_in) {
 }
 STATIC MP_DEFINE_CONST_FUN_OBJ_1(ppp_isconnected_obj, ppp_isconnected);
 
+STATIC mp_obj_t ppp_config(size_t n_args, const mp_obj_t *args, mp_map_t *kwargs) {
+    if (n_args != 1 && kwargs->used != 0) {
+        mp_raise_TypeError(MP_ERROR_TEXT("either pos or kw args are allowed"));
+    }
+    ppp_if_obj_t *self = MP_OBJ_TO_PTR(args[0]);
+
+    if (kwargs->used != 0) {
+        for (size_t i = 0; i < kwargs->alloc; i++) {
+            if (mp_map_slot_is_filled(kwargs, i)) {
+                switch (mp_obj_str_get_qstr(kwargs->table[i].key)) {
+                    default:
+                        break;
+                }
+            }
+        }
+        return mp_const_none;
+    }
+
+    if (n_args != 2) {
+        mp_raise_TypeError(MP_ERROR_TEXT("can query only one param"));
+    }
+
+    mp_obj_t val = mp_const_none;
+
+    switch (mp_obj_str_get_qstr(args[1])) {
+        case MP_QSTR_ifname: {
+            if (self->pcb != NULL) {
+                struct netif *pppif = ppp_netif(self->pcb);
+                char ifname[NETIF_NAMESIZE + 1] = {0};
+                netif_index_to_name(netif_get_index(pppif), ifname);
+                if (ifname[0] != 0) {
+                    val = mp_obj_new_str((char *)ifname, strlen(ifname));
+                }
+            }
+            break;
+        }
+        default:
+            mp_raise_ValueError(MP_ERROR_TEXT("unknown config param"));
+    }
+
+    return val;
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_KW(ppp_config_obj, 1, ppp_config);
+
 STATIC const mp_rom_map_elem_t ppp_if_locals_dict_table[] = {
     { MP_ROM_QSTR(MP_QSTR_active), MP_ROM_PTR(&ppp_active_obj) },
     { MP_ROM_QSTR(MP_QSTR_connect), MP_ROM_PTR(&ppp_connect_obj) },
     { MP_ROM_QSTR(MP_QSTR_isconnected), MP_ROM_PTR(&ppp_isconnected_obj) },
     { MP_ROM_QSTR(MP_QSTR_status), MP_ROM_PTR(&ppp_status_obj) },
+    { MP_ROM_QSTR(MP_QSTR_config), MP_ROM_PTR(&ppp_config_obj) },
     { MP_ROM_QSTR(MP_QSTR_ifconfig), MP_ROM_PTR(&ppp_ifconfig_obj) },
     { MP_ROM_QSTR(MP_QSTR___del__), MP_ROM_PTR(&ppp_delete_obj) },
     { MP_ROM_QSTR(MP_QSTR_AUTH_NONE), MP_ROM_INT(PPPAUTHTYPE_NONE) },
diff --git a/ports/esp32/network_wlan.c b/ports/esp32/network_wlan.c
index 8287731c31..58af9f3bc3 100644
--- a/ports/esp32/network_wlan.c
+++ b/ports/esp32/network_wlan.c
@@ -622,6 +622,10 @@ STATIC mp_obj_t network_wlan_config(size_t n_args, const mp_obj_t *args, mp_map_
             val = MP_OBJ_NEW_SMALL_INT(channel);
             break;
         }
+        case MP_QSTR_ifname: {
+            val = esp_ifname(self->netif);
+            break;
+        }
         case MP_QSTR_hostname:
         case MP_QSTR_dhcp_hostname: {
             // TODO: Deprecated. Use network.hostname() instead.
diff --git a/ports/esp32/partitions-ota.csv b/ports/esp32/partitions-4MiB-ota.csv
similarity index 100%
rename from ports/esp32/partitions-ota.csv
rename to ports/esp32/partitions-4MiB-ota.csv
diff --git a/ports/esp32/partitions.csv b/ports/esp32/partitions-4MiB.csv
similarity index 100%
rename from ports/esp32/partitions.csv
rename to ports/esp32/partitions-4MiB.csv
diff --git a/ports/esp32/uart.c b/ports/esp32/uart.c
index 358d434709..fc69e279e3 100644
--- a/ports/esp32/uart.c
+++ b/ports/esp32/uart.c
@@ -26,14 +26,16 @@
  * THE SOFTWARE.
  */
 
-#include <stdio.h>
-
-#include "hal/uart_hal.h"
 
 #include "py/runtime.h"
 #include "py/mphal.h"
 #include "uart.h"
 
+#if MICROPY_HW_ENABLE_UART_REPL
+
+#include <stdio.h>
+#include "hal/uart_hal.h"
+
 // Backwards compatibility for when MICROPY_HW_UART_REPL was a ESP-IDF UART
 // driver enum. Only UART_NUM_0 was supported with that version of the driver.
 #define UART_NUM_0 0
@@ -118,3 +120,5 @@ STATIC void IRAM_ATTR uart_irq_handler(void *arg) {
         }
     }
 }
+
+#endif // MICROPY_HW_ENABLE_UART_REPL
diff --git a/ports/esp32/uart.h b/ports/esp32/uart.h
index 6410db24c9..3d88eed825 100644
--- a/ports/esp32/uart.h
+++ b/ports/esp32/uart.h
@@ -30,9 +30,11 @@
 
 // Whether to enable the REPL on a UART.
 #ifndef MICROPY_HW_ENABLE_UART_REPL
-#define MICROPY_HW_ENABLE_UART_REPL (!CONFIG_USB_OTG_SUPPORTED && !CONFIG_ESP_CONSOLE_USB_SERIAL_JTAG)
+#define MICROPY_HW_ENABLE_UART_REPL (!CONFIG_USB_OTG_SUPPORTED && !CONFIG_ESP_CONSOLE_USB_CDC && !CONFIG_ESP_CONSOLE_USB_SERIAL_JTAG)
 #endif
 
+#if MICROPY_HW_ENABLE_UART_REPL
+
 #ifndef MICROPY_HW_UART_REPL
 #define MICROPY_HW_UART_REPL (0)
 #endif
@@ -44,4 +46,6 @@
 void uart_stdout_init(void);
 int uart_stdout_tx_strn(const char *str, size_t len);
 
+#endif // MICROPY_HW_ENABLE_UART_REPL
+
 #endif // MICROPY_INCLUDED_ESP32_UART_H
diff --git a/ports/esp32/usb.c b/ports/esp32/usb.c
index b9d99676d3..2e417755c9 100644
--- a/ports/esp32/usb.c
+++ b/ports/esp32/usb.c
@@ -28,7 +28,7 @@
 #include "py/mphal.h"
 #include "usb.h"
 
-#if CONFIG_USB_OTG_SUPPORTED
+#if CONFIG_USB_OTG_SUPPORTED && !CONFIG_ESP_CONSOLE_USB_CDC && !CONFIG_ESP_CONSOLE_USB_SERIAL_JTAG
 
 #include "esp_timer.h"
 #ifndef NO_QSTR
@@ -97,4 +97,4 @@ void usb_tx_strn(const char *str, size_t len) {
     }
 }
 
-#endif // CONFIG_USB_OTG_SUPPORTED
+#endif // CONFIG_USB_OTG_SUPPORTED && !CONFIG_ESP_CONSOLE_USB_CDC && !CONFIG_ESP_CONSOLE_USB_SERIAL_JTAG
diff --git a/ports/esp8266/Makefile b/ports/esp8266/Makefile
index 1cdcafa031..e4c907c57a 100644
--- a/ports/esp8266/Makefile
+++ b/ports/esp8266/Makefile
@@ -4,17 +4,25 @@ ifdef BOARD_DIR
 # the path as the board name.
 BOARD ?= $(notdir $(BOARD_DIR:/=))
 else
-# If not given on the command line, then default to GENERIC.
-BOARD ?= GENERIC
+# If not given on the command line, then default to ESP8266_GENERIC.
+BOARD ?= ESP8266_GENERIC
 BOARD_DIR ?= boards/$(BOARD)
 endif
 
 ifeq ($(wildcard $(BOARD_DIR)/.),)
+ifeq ($(findstring boards/GENERIC,$(BOARD_DIR)),boards/GENERIC)
+$(warning The GENERIC* boards have been renamed to ESP8266_GENERIC)
+endif
 $(error Invalid BOARD specified: $(BOARD_DIR))
 endif
 
-# If the build directory is not given, make it reflect the board name.
+# If the build directory is not given, make it reflect the board name (and
+# optionally the board variant).
+ifneq ($(BOARD_VARIANT),)
+BUILD ?= build-$(BOARD)-$(BOARD_VARIANT)
+else
 BUILD ?= build-$(BOARD)
+endif
 
 include ../../py/mkenv.mk
 
@@ -40,7 +48,7 @@ include $(TOP)/extmod/extmod.mk
 
 GIT_SUBMODULES += lib/axtls lib/berkeley-db-1.xx
 
-FWBIN = $(BUILD)/firmware-combined.bin
+FWBIN = $(BUILD)/firmware.bin
 PORT ?= /dev/ttyACM0
 BAUD ?= 115200
 FLASH_MODE ?= qio
@@ -202,7 +210,7 @@ FROZEN_EXTRA_DEPS = $(CONFVARS_FILE)
 
 .PHONY: deploy
 
-deploy: $(BUILD)/firmware-combined.bin
+deploy: $(FWBIN)
 	$(ECHO) "Writing $< to the board"
 	$(Q)esptool.py --port $(PORT) --baud $(BAUD) write_flash --verify --flash_size=$(FLASH_SIZE) --flash_mode=$(FLASH_MODE) 0 $<
 
@@ -213,20 +221,26 @@ erase:
 reset:
 	echo -e "\r\nimport machine; machine.reset()\r\n" >$(PORT)
 
+ifeq ($(BOARD_VARIANT),OTA)
+$(FWBIN): $(BUILD)/firmware.elf
+	$(ECHO) "Create $@"
+	$(Q)esptool.py elf2image $^
+	$(Q)$(PYTHON) makeimg.py $(BUILD)/firmware.elf-0x00000.bin $(BUILD)/firmware.elf-0x[0-5][1-f]000.bin $(BUILD)/firmware-ota.bin
+
+	$(Q)cat $(YAOTA8266)/yaota8266.bin $(BUILD)/firmware-ota.bin > $@
+	$(Q)$(PYTHON) $(YAOTA8266)/ota-client/ota_client.py sign $@
+else
 $(FWBIN): $(BUILD)/firmware.elf
 	$(ECHO) "Create $@"
 	$(Q)esptool.py elf2image $^
 	$(Q)$(PYTHON) makeimg.py $(BUILD)/firmware.elf-0x00000.bin $(BUILD)/firmware.elf-0x[0-5][1-f]000.bin $@
+endif
 
 $(BUILD)/firmware.elf: $(OBJ)
 	$(ECHO) "LINK $@"
 	$(Q)$(LD) $(LDFLAGS) -o $@ $^ $(LIBS)
 	$(Q)$(SIZE) $@
 
-ota:
-	rm -f $(BUILD)/firmware.elf $(BUILD)/firmware.elf*.bin
-	$(MAKE) LD_FILES=boards/esp8266_ota.ld FWBIN=$(BUILD)/firmware-ota.bin
-
 include $(TOP)/py/mkrules.mk
 
 clean-modules:
diff --git a/ports/esp8266/README.md b/ports/esp8266/README.md
index 1e0cae2139..561c771403 100644
--- a/ports/esp8266/README.md
+++ b/ports/esp8266/README.md
@@ -23,6 +23,9 @@ Supported features include:
 
 Documentation is available at http://docs.micropython.org/en/latest/esp8266/quickref.html.
 
+The default build requires a 2MiB flash chip, but see below for support for
+1MiB and 512kiB options.
+
 Build instructions
 ------------------
 
@@ -67,10 +70,10 @@ Then to compile the ESP8266 firmware:
 
 ```
 $ cd ports/esp8266
-$ docker run --rm -v $HOME:$HOME -u $UID -w $PWD larsks/esp-open-sdk make -j BOARD=GENERIC
+$ docker run --rm -v $HOME:$HOME -u $UID -w $PWD larsks/esp-open-sdk make -j BOARD=ESP8266_GENERIC
 ```
 
-This will produce binary images in the `build-GENERIC/` subdirectory.
+This will produce binary images in the `build-ESP8266_GENERIC/` subdirectory.
 Substitute the board for whichever board you're using.
 
 __Building with a local toolchain__
@@ -106,10 +109,10 @@ Then to compile the ESP8266 firmware:
 
 ```
 $ cd ports/esp8266
-$ make -j BOARD=GENERIC
+$ make -j BOARD=ESP8266_GENERIC
 ```
 
-This will produce binary images in the `build-GENERIC/` subdirectory.
+This will produce binary images in the `build-ESP8266_GENERIC/` subdirectory.
 Substitute the board for whichever board you're using.
 
 
@@ -149,26 +152,30 @@ $ make PORT=/dev/ttyUSB0 FLASH_MODE=qio FLASH_SIZE=32m deploy
 (note that flash size is in megabits)
 
 If you want to flash manually using `esptool.py` directly, the image produced is
-`build-GENERIC/firmware-combined.bin`, to be flashed at 0x00000.
+`build-ESP8266_GENERIC/firmware.bin`, to be flashed at 0x00000.
 
-The default board definition is the directory `boards/GENERIC`.
+The default board definition is the directory `boards/ESP8266_GENERIC`.
 For a custom configuration you can define your own board in the directory `boards/`.
 
-The `BOARD` variable can be set on the make command line, for example:
+__Reduced FlashROM variants__
+
+The normal build described above requires modules with at least 2MiB of
+FlashROM onboard. There's a special configuration for 512kiB modules, which can
+be built with the `FLASH_512K` variant. This configuration is highly limited,
+lacks filesystem support, WebREPL, and has many other features disabled. It's
+mostly suitable for advanced users who are interested to fine-tune options to
+achieve a required setup. If you are an end user, please consider using a
+module with at least 2MiB of FlashROM.
+
+A variant is also provided for 1MiB modules which just lacks the included
+micropython-lib packages.
+
+The variant can be set on the make command line, for example:
 ```bash
-$ make BOARD=GENERIC_512K
+$ make BOARD=ESP8266_GENERIC BOARD_VARIANT=FLASH_512K
+$ make BOARD=ESP8266_GENERIC BOARD_VARIANT=FLASH_1M
 ```
 
-__512KB FlashROM version__
-
-The normal build described above requires modules with at least 1MB of FlashROM
-onboard. There's a special configuration for 512KB modules, which can be
-built with `make BOARD=GENERIC_512K`. This configuration is highly limited, lacks
-filesystem support, WebREPL, and has many other features disabled. It's mostly
-suitable for advanced users who are interested to fine-tune options to achieve a
-required setup. If you are an end user, please consider using a module with at
-least 1MB of FlashROM.
-
 First start
 -----------
 
diff --git a/ports/esp8266/boards/ESP8266_GENERIC/_boot.py b/ports/esp8266/boards/ESP8266_GENERIC/_boot.py
new file mode 100644
index 0000000000..16da8bc4c3
--- /dev/null
+++ b/ports/esp8266/boards/ESP8266_GENERIC/_boot.py
@@ -0,0 +1,6 @@
+# Minimal _boot.py for the 512kiB variant. Does not set up a block device or
+# filesystem. Other variants use esp8266/modules/_boot.py.
+
+import gc
+
+gc.threshold((gc.mem_free() + gc.mem_alloc()) // 4)
diff --git a/ports/esp32/boards/GENERIC_SPIRAM/board.json b/ports/esp8266/boards/ESP8266_GENERIC/board.json
similarity index 56%
rename from ports/esp32/boards/GENERIC_SPIRAM/board.json
rename to ports/esp8266/boards/ESP8266_GENERIC/board.json
index afb57b2ed1..2b3a6b5507 100644
--- a/ports/esp32/boards/GENERIC_SPIRAM/board.json
+++ b/ports/esp8266/boards/ESP8266_GENERIC/board.json
@@ -4,20 +4,20 @@
     ],
     "docs": "",
     "features": [
-        "BLE",
-        "SPIRAM",
+        "External Flash",
         "WiFi"
     ],
-    "id": "esp32spiram",
     "images": [
-        "esp32_psram.jpg"
+        "esp8266.jpg"
     ],
-    "mcu": "esp32",
-    "product": "ESP32 with SPIRAM",
+    "mcu": "esp8266",
+    "product": "ESP8266",
     "thumbnail": "",
     "url": "https://www.espressif.com/en/products/modules",
     "variants": {
-        "idf3": "Compiled with IDF 3.x"
+        "OTA": "OTA compatible",
+        "FLASH_1M": "1MiB flash",
+        "FLASH_512K": "512kiB flash"
     },
     "vendor": "Espressif"
 }
diff --git a/ports/esp8266/boards/GENERIC/board.md b/ports/esp8266/boards/ESP8266_GENERIC/board.md
similarity index 58%
rename from ports/esp8266/boards/GENERIC/board.md
rename to ports/esp8266/boards/ESP8266_GENERIC/board.md
index fa0cf410d6..96fbab617a 100644
--- a/ports/esp8266/boards/GENERIC/board.md
+++ b/ports/esp8266/boards/ESP8266_GENERIC/board.md
@@ -1,6 +1,13 @@
-The following are daily builds of the ESP8266 firmware for boards with at
-least 2MiB of flash.  They have the latest features and bug fixes, WebREPL is
-not automatically started, and debugging is enabled by default.
+The following are daily builds of the ESP8266 firmware. This will work on
+boards with at least 2MiB of flash.  They have the latest features and bug
+fixes, WebREPL is not automatically started, and debugging is enabled by
+default.
+
+For boards with 1MiB or 512kiB of flash, two variants are provided with reduced
+functionality. The 1MiB variant removes asyncio and FAT-filesystem support as
+well as some modules from micropython-lib. The 512kiB variant further removes
+all filesystem support, as well as framebuffer support, some Python language
+features, and has less detailed error messages.
 
 Note: v1.12-334 and newer (including v1.13) require an ESP8266 module with
 2MiB of flash or more, and use littlefs as the filesystem by default.  When
diff --git a/ports/esp8266/boards/GENERIC/manifest.py b/ports/esp8266/boards/ESP8266_GENERIC/manifest_2MiB.py
similarity index 100%
rename from ports/esp8266/boards/GENERIC/manifest.py
rename to ports/esp8266/boards/ESP8266_GENERIC/manifest_2MiB.py
diff --git a/ports/esp8266/boards/GENERIC_512K/manifest.py b/ports/esp8266/boards/ESP8266_GENERIC/manifest_512kiB.py
similarity index 100%
rename from ports/esp8266/boards/GENERIC_512K/manifest.py
rename to ports/esp8266/boards/ESP8266_GENERIC/manifest_512kiB.py
diff --git a/ports/esp8266/boards/ESP8266_GENERIC/mpconfigboard.h b/ports/esp8266/boards/ESP8266_GENERIC/mpconfigboard.h
new file mode 100644
index 0000000000..3a9c40e795
--- /dev/null
+++ b/ports/esp8266/boards/ESP8266_GENERIC/mpconfigboard.h
@@ -0,0 +1,52 @@
+#if defined(MICROPY_ESP8266_2M)
+
+#define MICROPY_HW_BOARD_NAME "ESP module"
+#define MICROPY_HW_MCU_NAME "ESP8266"
+
+#define MICROPY_PERSISTENT_CODE_LOAD    (1)
+#define MICROPY_EMIT_XTENSA             (1)
+#define MICROPY_EMIT_INLINE_XTENSA      (1)
+
+#define MICROPY_DEBUG_PRINTERS          (1)
+#define MICROPY_ERROR_REPORTING         (MICROPY_ERROR_REPORTING_NORMAL)
+
+#define MICROPY_READER_VFS              (MICROPY_VFS)
+#define MICROPY_VFS                     (1)
+
+#define MICROPY_PY_CRYPTOLIB            (1)
+
+#elif defined(MICROPY_ESP8266_1M)
+
+#define MICROPY_HW_BOARD_NAME "ESP module (1M)"
+#define MICROPY_HW_MCU_NAME "ESP8266"
+
+#define MICROPY_PERSISTENT_CODE_LOAD    (1)
+#define MICROPY_EMIT_XTENSA             (1)
+#define MICROPY_EMIT_INLINE_XTENSA      (1)
+
+#define MICROPY_DEBUG_PRINTERS          (1)
+#define MICROPY_ERROR_REPORTING         (MICROPY_ERROR_REPORTING_NORMAL)
+
+#define MICROPY_READER_VFS              (MICROPY_VFS)
+#define MICROPY_VFS                     (1)
+
+
+#define MICROPY_PY_CRYPTOLIB            (1)
+
+#elif defined(MICROPY_ESP8266_512K)
+
+#define MICROPY_HW_BOARD_NAME "ESP module (512K)"
+#define MICROPY_HW_MCU_NAME "ESP8266"
+
+#define MICROPY_ERROR_REPORTING         (MICROPY_ERROR_REPORTING_TERSE)
+
+#define MICROPY_PY_FSTRINGS             (0)
+#define MICROPY_PY_BUILTINS_SLICE_ATTRS (0)
+#define MICROPY_PY_ALL_SPECIAL_METHODS  (0)
+#define MICROPY_PY_REVERSE_SPECIAL_METHODS (0)
+#define MICROPY_PY_SYS_STDIO_BUFFER     (0)
+#define MICROPY_PY_ASYNCIO              (0)
+#define MICROPY_PY_RE_SUB               (0)
+#define MICROPY_PY_FRAMEBUF             (0)
+
+#endif
diff --git a/ports/esp8266/boards/ESP8266_GENERIC/mpconfigboard.mk b/ports/esp8266/boards/ESP8266_GENERIC/mpconfigboard.mk
new file mode 100644
index 0000000000..2eb78d7e85
--- /dev/null
+++ b/ports/esp8266/boards/ESP8266_GENERIC/mpconfigboard.mk
@@ -0,0 +1,50 @@
+ifeq ($(BOARD_VARIANT),)
+LD_FILES = boards/esp8266_2MiB.ld
+
+MICROPY_ESPNOW ?= 1
+MICROPY_PY_BTREE ?= 1
+MICROPY_VFS_FAT ?= 1
+MICROPY_VFS_LFS2 ?= 1
+
+# Add asyncio and extra micropython-lib packages (in addition to the port manifest).
+FROZEN_MANIFEST ?= $(BOARD_DIR)/manifest_2MiB.py
+
+# Configure mpconfigboard.h.
+CFLAGS += -DMICROPY_ESP8266_2M
+endif
+
+ifeq ($(BOARD_VARIANT),FLASH_1M)
+LD_FILES = boards/esp8266_1MiB.ld
+
+MICROPY_ESPNOW ?= 1
+MICROPY_PY_BTREE ?= 1
+MICROPY_VFS_LFS2 ?= 1
+
+# Note: Implicitly uses the port manifest.
+
+# Configure mpconfigboard.h.
+CFLAGS += -DMICROPY_ESP8266_1M
+endif
+
+ifeq ($(BOARD_VARIANT),OTA)
+LD_FILES = boards/esp8266_ota.ld
+
+MICROPY_ESPNOW ?= 1
+MICROPY_PY_BTREE ?= 1
+MICROPY_VFS_LFS2 ?= 1
+
+# Note: Implicitly uses the port manifest.
+
+# Configure mpconfigboard.h.
+CFLAGS += -DMICROPY_ESP8266_1M
+endif
+
+ifeq ($(BOARD_VARIANT),FLASH_512K)
+LD_FILES = boards/esp8266_512kiB.ld
+
+# Note: Use the minimal manifest.py.
+FROZEN_MANIFEST ?= $(BOARD_DIR)/manifest_512kiB.py
+
+# Configure mpconfigboard.h.
+CFLAGS += -DMICROPY_ESP8266_512K
+endif
diff --git a/ports/esp8266/boards/GENERIC/board.json b/ports/esp8266/boards/GENERIC/board.json
deleted file mode 100644
index 46c2659d8a..0000000000
--- a/ports/esp8266/boards/GENERIC/board.json
+++ /dev/null
@@ -1,19 +0,0 @@
-{
-    "deploy": [
-        "../deploy.md"
-    ],
-    "docs": "",
-    "features": [
-        "WiFi"
-    ],
-    "id": "esp8266",
-    "images": [],
-    "mcu": "esp8266",
-    "product": "ESP8266 with 2MiB+ flash",
-    "thumbnail": "",
-    "url": "https://www.espressif.com/en/products/modules",
-    "variants": {
-        "ota": "OTA compatible"
-    },
-    "vendor": "Espressif"
-}
diff --git a/ports/esp8266/boards/GENERIC/mpconfigboard.h b/ports/esp8266/boards/GENERIC/mpconfigboard.h
deleted file mode 100644
index 52c93f83a3..0000000000
--- a/ports/esp8266/boards/GENERIC/mpconfigboard.h
+++ /dev/null
@@ -1,14 +0,0 @@
-#define MICROPY_HW_BOARD_NAME "ESP module"
-#define MICROPY_HW_MCU_NAME "ESP8266"
-
-#define MICROPY_PERSISTENT_CODE_LOAD    (1)
-#define MICROPY_EMIT_XTENSA             (1)
-#define MICROPY_EMIT_INLINE_XTENSA      (1)
-
-#define MICROPY_DEBUG_PRINTERS          (1)
-#define MICROPY_ERROR_REPORTING         (MICROPY_ERROR_REPORTING_NORMAL)
-
-#define MICROPY_READER_VFS              (MICROPY_VFS)
-#define MICROPY_VFS                     (1)
-
-#define MICROPY_PY_CRYPTOLIB            (1)
diff --git a/ports/esp8266/boards/GENERIC/mpconfigboard.mk b/ports/esp8266/boards/GENERIC/mpconfigboard.mk
deleted file mode 100644
index 8d7babdc84..0000000000
--- a/ports/esp8266/boards/GENERIC/mpconfigboard.mk
+++ /dev/null
@@ -1,8 +0,0 @@
-LD_FILES = boards/esp8266_2m.ld
-
-MICROPY_ESPNOW ?= 1
-MICROPY_PY_BTREE ?= 1
-MICROPY_VFS_FAT ?= 1
-MICROPY_VFS_LFS2 ?= 1
-
-FROZEN_MANIFEST ?= $(BOARD_DIR)/manifest.py
diff --git a/ports/esp8266/boards/GENERIC_1M/board.json b/ports/esp8266/boards/GENERIC_1M/board.json
deleted file mode 100644
index 2ef4bd99fa..0000000000
--- a/ports/esp8266/boards/GENERIC_1M/board.json
+++ /dev/null
@@ -1,16 +0,0 @@
-{
-    "deploy": [
-        "../deploy.md"
-    ],
-    "docs": "",
-    "features": [
-        "WiFi"
-    ],
-    "id": "esp8266-1m",
-    "images": [],
-    "mcu": "esp8266",
-    "product": "ESP8266 with 1MiB flash",
-    "thumbnail": "",
-    "url": "https://www.espressif.com/en/products/modules",
-    "vendor": "Espressif"
-}
diff --git a/ports/esp8266/boards/GENERIC_1M/board.md b/ports/esp8266/boards/GENERIC_1M/board.md
deleted file mode 100644
index 17cc6e3a6b..0000000000
--- a/ports/esp8266/boards/GENERIC_1M/board.md
+++ /dev/null
@@ -1,5 +0,0 @@
-The following are daily builds of the ESP8266 firmware tailored for modules with
-only 1MiB of flash.  This firmware uses littlefs as the filesystem.
-When upgrading from older firmware that uses a FAT filesystem please backup your files
-first, and either erase all flash before upgrading, or after upgrading execute
-`os.VfsLfs2.mkfs(bdev)`.
diff --git a/ports/esp8266/boards/GENERIC_1M/mpconfigboard.h b/ports/esp8266/boards/GENERIC_1M/mpconfigboard.h
deleted file mode 100644
index 41752e692b..0000000000
--- a/ports/esp8266/boards/GENERIC_1M/mpconfigboard.h
+++ /dev/null
@@ -1,17 +0,0 @@
-#define MICROPY_HW_BOARD_NAME "ESP module (1M)"
-#define MICROPY_HW_MCU_NAME "ESP8266"
-
-#define MICROPY_PERSISTENT_CODE_LOAD    (1)
-#define MICROPY_EMIT_XTENSA             (1)
-#define MICROPY_EMIT_INLINE_XTENSA      (1)
-
-#define MICROPY_DEBUG_PRINTERS          (1)
-#define MICROPY_ERROR_REPORTING         (MICROPY_ERROR_REPORTING_NORMAL)
-
-#define MICROPY_READER_VFS              (MICROPY_VFS)
-#define MICROPY_VFS                     (1)
-
-#define MICROPY_PY_FSTRINGS             (0)
-#define MICROPY_PY_REVERSE_SPECIAL_METHODS (0)
-#define MICROPY_PY_ASYNCIO              (0)
-#define MICROPY_PY_CRYPTOLIB            (1)
diff --git a/ports/esp8266/boards/GENERIC_1M/mpconfigboard.mk b/ports/esp8266/boards/GENERIC_1M/mpconfigboard.mk
deleted file mode 100644
index adc31702e0..0000000000
--- a/ports/esp8266/boards/GENERIC_1M/mpconfigboard.mk
+++ /dev/null
@@ -1,5 +0,0 @@
-LD_FILES = boards/esp8266_1m.ld
-
-MICROPY_ESPNOW ?= 1
-MICROPY_PY_BTREE ?= 1
-MICROPY_VFS_LFS2 ?= 1
diff --git a/ports/esp8266/boards/GENERIC_512K/_boot.py b/ports/esp8266/boards/GENERIC_512K/_boot.py
deleted file mode 100644
index 1a55cfd36c..0000000000
--- a/ports/esp8266/boards/GENERIC_512K/_boot.py
+++ /dev/null
@@ -1,3 +0,0 @@
-import gc
-
-gc.threshold((gc.mem_free() + gc.mem_alloc()) // 4)
diff --git a/ports/esp8266/boards/GENERIC_512K/board.json b/ports/esp8266/boards/GENERIC_512K/board.json
deleted file mode 100644
index 10050592cf..0000000000
--- a/ports/esp8266/boards/GENERIC_512K/board.json
+++ /dev/null
@@ -1,16 +0,0 @@
-{
-    "deploy": [
-        "../deploy.md"
-    ],
-    "docs": "",
-    "features": [
-        "WiFi"
-    ],
-    "id": "esp8266-512k",
-    "images": [],
-    "mcu": "esp8266",
-    "product": "ESP8266 with 512kiB flash",
-    "thumbnail": "",
-    "url": "https://www.espressif.com/en/products/modules",
-    "vendor": "Espressif"
-}
diff --git a/ports/esp8266/boards/GENERIC_512K/board.md b/ports/esp8266/boards/GENERIC_512K/board.md
deleted file mode 100644
index 1f6e2c7907..0000000000
--- a/ports/esp8266/boards/GENERIC_512K/board.md
+++ /dev/null
@@ -1,3 +0,0 @@
-The following are daily builds of the ESP8266 firmware tailored for modules with
-only 512kiB of flash.  Certain features are disabled to get the firmware down
-to this size.
diff --git a/ports/esp8266/boards/GENERIC_512K/mpconfigboard.h b/ports/esp8266/boards/GENERIC_512K/mpconfigboard.h
deleted file mode 100644
index c29e23d5ad..0000000000
--- a/ports/esp8266/boards/GENERIC_512K/mpconfigboard.h
+++ /dev/null
@@ -1,13 +0,0 @@
-#define MICROPY_HW_BOARD_NAME "ESP module (512K)"
-#define MICROPY_HW_MCU_NAME "ESP8266"
-
-#define MICROPY_ERROR_REPORTING         (MICROPY_ERROR_REPORTING_TERSE)
-
-#define MICROPY_PY_FSTRINGS             (0)
-#define MICROPY_PY_BUILTINS_SLICE_ATTRS (0)
-#define MICROPY_PY_ALL_SPECIAL_METHODS  (0)
-#define MICROPY_PY_REVERSE_SPECIAL_METHODS (0)
-#define MICROPY_PY_SYS_STDIO_BUFFER     (0)
-#define MICROPY_PY_ASYNCIO              (0)
-#define MICROPY_PY_RE_SUB               (0)
-#define MICROPY_PY_FRAMEBUF             (0)
diff --git a/ports/esp8266/boards/GENERIC_512K/mpconfigboard.mk b/ports/esp8266/boards/GENERIC_512K/mpconfigboard.mk
deleted file mode 100644
index 120351909b..0000000000
--- a/ports/esp8266/boards/GENERIC_512K/mpconfigboard.mk
+++ /dev/null
@@ -1,3 +0,0 @@
-LD_FILES = boards/esp8266_512k.ld
-
-FROZEN_MANIFEST ?= $(BOARD_DIR)/manifest.py
diff --git a/ports/esp8266/boards/esp8266_1m.ld b/ports/esp8266/boards/esp8266_1MiB.ld
similarity index 100%
rename from ports/esp8266/boards/esp8266_1m.ld
rename to ports/esp8266/boards/esp8266_1MiB.ld
diff --git a/ports/esp8266/boards/esp8266_2m.ld b/ports/esp8266/boards/esp8266_2MiB.ld
similarity index 100%
rename from ports/esp8266/boards/esp8266_2m.ld
rename to ports/esp8266/boards/esp8266_2MiB.ld
diff --git a/ports/esp8266/boards/esp8266_512k.ld b/ports/esp8266/boards/esp8266_512kiB.ld
similarity index 100%
rename from ports/esp8266/boards/esp8266_512k.ld
rename to ports/esp8266/boards/esp8266_512kiB.ld
diff --git a/ports/mimxrt/Makefile b/ports/mimxrt/Makefile
index 63cba7d7a6..ead206e5e2 100644
--- a/ports/mimxrt/Makefile
+++ b/ports/mimxrt/Makefile
@@ -216,6 +216,7 @@ SRC_C += \
 	pendsv.c \
 	pin.c \
 	sdcard.c \
+	sdio.c \
 	systick.c \
 	ticks.c \
 	tusb_port.c \
@@ -263,6 +264,14 @@ else
     SRC_HAL_C += hal/$(FLEXSPI_FLASH_TYPE)_config.c
 endif
 
+ifeq ($(MICROPY_PY_BLUETOOTH),1)
+SRC_C += mpbthciport.c
+endif # MICROPY_PY_BLUETOOTH
+
+ifeq ($(MICROPY_BLUETOOTH_NIMBLE),1)
+SRC_C += mpnimbleport.c
+endif
+
 # Math library source files
 ifeq ($(MICROPY_FLOAT_IMPL),double)
     LIBM_SRC_C += $(addprefix lib/libm_dbl/,\
@@ -397,6 +406,10 @@ CFLAGS += \
 	-DFSL_FEATURE_PHYKSZ8081_USE_RMII50M_MODE=1
 endif
 
+ifdef MICROPY_HW_FLASH_CLK
+	CFLAGS += -DMICROPY_HW_FLASH_CLK=$(MICROPY_HW_FLASH_CLK)
+endif
+
 CFLAGS += $(CFLAGS_EXTRA)
 
 MPY_CROSS_FLAGS += -march=armv7m
@@ -444,6 +457,7 @@ OBJ += $(PY_O)
 OBJ += $(LIBM_O)
 OBJ += $(addprefix $(BUILD)/, $(SRC_C:.c=.o))
 OBJ += $(addprefix $(BUILD)/, $(SHARED_SRC_C:.c=.o))
+OBJ += $(addprefix $(BUILD)/, $(DRIVERS_SRC_C:.c=.o))
 OBJ += $(addprefix $(BUILD)/, $(SRC_S:.s=.o))
 OBJ += $(addprefix $(BUILD)/, $(SRC_SS:.S=.o))
 OBJ += $(addprefix $(BUILD)/, $(SRC_TINYUSB_C:.c=.o))
diff --git a/ports/mimxrt/board_init.c b/ports/mimxrt/board_init.c
index 78001862f0..88de27ea77 100644
--- a/ports/mimxrt/board_init.c
+++ b/ports/mimxrt/board_init.c
@@ -39,6 +39,7 @@
 
 #include CLOCK_CONFIG_H
 #include "modmachine.h"
+#include "irq.h"
 
 const uint8_t dcd_data[] = { 0x00 };
 
@@ -63,6 +64,7 @@ void board_init(void) {
 
     // 1ms tick timer
     SysTick_Config(SystemCoreClock / 1000);
+    NVIC_SetPriority(SysTick_IRQn, IRQ_PRI_SYSTICK);
 
     // USB0
     usb_phy0_init(0b0111, 0b0110, 0b0110);  // Configure nominal values for D_CAL and TXCAL45DP/DN
diff --git a/ports/mimxrt/boards/ADAFRUIT_METRO_M7/board.json b/ports/mimxrt/boards/ADAFRUIT_METRO_M7/board.json
index c96e9b08fe..9f260b3a00 100644
--- a/ports/mimxrt/boards/ADAFRUIT_METRO_M7/board.json
+++ b/ports/mimxrt/boards/ADAFRUIT_METRO_M7/board.json
@@ -4,16 +4,12 @@
     ],
     "docs": "",
     "features": [
-        "USB-C",
-        "SPI",
-        "I2C",
-        "UART",
+        "BLE",
+        "External Flash",
+        "JST-SH",
         "RGB LED",
-        "QSPI Flash",
-        "QWIIC",
-        "JLink",
-        "WiFi",
-        "BLE"
+        "USB-C",
+        "WiFi"
     ],
     "images": [
         "Metro_M7.jpg"
diff --git a/ports/mimxrt/boards/ADAFRUIT_METRO_M7/mpconfigboard.h b/ports/mimxrt/boards/ADAFRUIT_METRO_M7/mpconfigboard.h
index ac9cf97058..7d759df5e6 100644
--- a/ports/mimxrt/boards/ADAFRUIT_METRO_M7/mpconfigboard.h
+++ b/ports/mimxrt/boards/ADAFRUIT_METRO_M7/mpconfigboard.h
@@ -23,6 +23,12 @@
     { 0 }, { 0 }, \
     { IOMUXC_GPIO_AD_02_LPUART4_TXD }, { IOMUXC_GPIO_AD_01_LPUART4_RXD },
 
+#define IOMUX_TABLE_UART_CTS_RTS \
+    { IOMUXC_GPIO_08_LPUART1_CTS_B }, { IOMUXC_GPIO_07_LPUART1_RTS_B }, \
+    { IOMUXC_GPIO_AD_14_LPUART3_CTS_B }, { 0 }, \
+    { 0 }, { 0 }, \
+    { IOMUXC_GPIO_AD_14_LPUART4_CTS_B }, { 0 },
+
 #define MICROPY_HW_SPI_INDEX { 1 }
 
 #define IOMUX_TABLE_SPI \
diff --git a/ports/mimxrt/boards/MIMXRT1010_EVK/board.json b/ports/mimxrt/boards/MIMXRT1010_EVK/board.json
index 4bf9ce0524..3fc3403c06 100644
--- a/ports/mimxrt/boards/MIMXRT1010_EVK/board.json
+++ b/ports/mimxrt/boards/MIMXRT1010_EVK/board.json
@@ -4,12 +4,10 @@
     ],
     "docs": "",
     "features": [
-        "MicroUSB",
+        "Audio Codec",
+        "External Flash",
         "Microphone",
-        "AudioCodec",
-        "SPDIF",
-        "OpenSDA",
-        "JLink"
+        "USB"
     ],
     "images": [
         "i.MXRT1010-TOP.jpg"
diff --git a/ports/mimxrt/boards/MIMXRT1010_EVK/mpconfigboard.h b/ports/mimxrt/boards/MIMXRT1010_EVK/mpconfigboard.h
index eff9e9c2cd..26811fdab8 100644
--- a/ports/mimxrt/boards/MIMXRT1010_EVK/mpconfigboard.h
+++ b/ports/mimxrt/boards/MIMXRT1010_EVK/mpconfigboard.h
@@ -23,6 +23,12 @@
     { IOMUXC_GPIO_08_LPUART3_TXD }, { IOMUXC_GPIO_AD_07_LPUART3_RXD }, \
     { IOMUXC_GPIO_AD_02_LPUART4_TXD }, { IOMUXC_GPIO_AD_01_LPUART4_RXD },
 
+#define IOMUX_TABLE_UART_CTS_RTS \
+    { IOMUXC_GPIO_08_LPUART1_CTS_B }, { IOMUXC_GPIO_07_LPUART1_RTS_B }, \
+    { 0 }, { 0 }, \
+    { 0 }, { 0 }, \
+    { IOMUXC_GPIO_AD_14_LPUART4_CTS_B }, { IOMUXC_GPIO_AD_13_LPUART4_RTS_B },
+
 #define MICROPY_HW_SPI_INDEX { 1 }
 
 #define IOMUX_TABLE_SPI \
diff --git a/ports/mimxrt/boards/MIMXRT1015_EVK/board.json b/ports/mimxrt/boards/MIMXRT1015_EVK/board.json
index 78044c134e..d0bdd920bc 100644
--- a/ports/mimxrt/boards/MIMXRT1015_EVK/board.json
+++ b/ports/mimxrt/boards/MIMXRT1015_EVK/board.json
@@ -4,13 +4,10 @@
     ],
     "docs": "",
     "features": [
-        "MicroSD",
-        "MicroUSB",
+        "Audio Codec",
+        "External Flash",
         "Microphone",
-        "AudioCodec",
-        "CAN",
-        "OpenSDA",
-        "JLink"
+        "USB"
     ],
     "images": [
         "MIMXRT1015-EVK-TOP.jpg"
diff --git a/ports/mimxrt/boards/MIMXRT1015_EVK/mpconfigboard.h b/ports/mimxrt/boards/MIMXRT1015_EVK/mpconfigboard.h
index f37ba824f4..655bb62c27 100644
--- a/ports/mimxrt/boards/MIMXRT1015_EVK/mpconfigboard.h
+++ b/ports/mimxrt/boards/MIMXRT1015_EVK/mpconfigboard.h
@@ -28,6 +28,12 @@
     { IOMUXC_GPIO_AD_B0_14_LPUART3_TX }, { IOMUXC_GPIO_AD_B0_15_LPUART3_RX }, \
     { IOMUXC_GPIO_EMC_32_LPUART4_TX },   { IOMUXC_GPIO_EMC_33_LPUART4_RX }, \
 
+#define IOMUX_TABLE_UART_CTS_RTS \
+    { IOMUXC_GPIO_AD_B0_08_LPUART1_CTS_B }, { IOMUXC_GPIO_AD_B0_09_LPUART1_RTS_B }, \
+    { 0 }, { 0 }, \
+    { IOMUXC_GPIO_AD_B0_12_LPUART3_CTS_B }, { IOMUXC_GPIO_AD_B0_13_LPUART3_RTS_B }, \
+    { 0 }, { 0 },
+
 #define MICROPY_HW_SPI_INDEX { 1 }
 
 #define IOMUX_TABLE_SPI \
diff --git a/ports/mimxrt/boards/MIMXRT1020_EVK/board.json b/ports/mimxrt/boards/MIMXRT1020_EVK/board.json
index cc74c25fed..4da224fc99 100644
--- a/ports/mimxrt/boards/MIMXRT1020_EVK/board.json
+++ b/ports/mimxrt/boards/MIMXRT1020_EVK/board.json
@@ -4,15 +4,14 @@
     ],
     "docs": "",
     "features": [
-        "Ethernet",
-        "SDRAM",
-        "MicroSD",
-        "MicroUSB",
-        "Microphone",
-        "AudioCodec",
+        "Audio Codec",
         "CAN",
-        "OpenSDA",
-        "JLink"
+        "Ethernet",
+        "External Flash",
+        "External RAM",
+        "Microphone",
+        "USB",
+        "microSD"
     ],
     "images": [
         "MIMXRT-1020-EVKBD.jpg"
diff --git a/ports/mimxrt/boards/MIMXRT1020_EVK/mpconfigboard.h b/ports/mimxrt/boards/MIMXRT1020_EVK/mpconfigboard.h
index 390e91814d..8b7316c8da 100644
--- a/ports/mimxrt/boards/MIMXRT1020_EVK/mpconfigboard.h
+++ b/ports/mimxrt/boards/MIMXRT1020_EVK/mpconfigboard.h
@@ -34,6 +34,16 @@
     { 0 }, { 0 }, \
     { IOMUXC_GPIO_SD_B1_02_LPUART8_TX }, { IOMUXC_GPIO_SD_B1_03_LPUART8_RX },
 
+#define IOMUX_TABLE_UART_CTS_RTS \
+    { IOMUXC_GPIO_AD_B0_08_LPUART1_CTS_B }, { IOMUXC_GPIO_AD_B0_09_LPUART1_RTS_B }, \
+    { IOMUXC_GPIO_AD_B1_06_LPUART2_CTS_B }, { IOMUXC_GPIO_AD_B1_07_LPUART2_RTS_B }, \
+    { IOMUXC_GPIO_AD_B0_12_LPUART3_CTS_B }, { IOMUXC_GPIO_AD_B0_13_LPUART3_RTS_B }, \
+    { IOMUXC_GPIO_EMC_00_LPUART4_CTS_B }, { IOMUXC_GPIO_EMC_01_LPUART4_RTS_B }, \
+    { IOMUXC_GPIO_EMC_36_LPUART5_CTS_B }, { IOMUXC_GPIO_EMC_37_LPUART5_RTS_B }, \
+    { 0 }, { 0 }, \
+    { 0 }, { 0 }, \
+    { IOMUXC_GPIO_EMC_24_LPUART8_CTS_B }, { IOMUXC_GPIO_EMC_25_LPUART8_RTS_B },
+
 #define MICROPY_HW_SPI_INDEX { 1, 3 }
 
 #define IOMUX_TABLE_SPI \
diff --git a/ports/mimxrt/boards/MIMXRT1050_EVK/board.json b/ports/mimxrt/boards/MIMXRT1050_EVK/board.json
index d99ad9fcfd..d7c82358cc 100644
--- a/ports/mimxrt/boards/MIMXRT1050_EVK/board.json
+++ b/ports/mimxrt/boards/MIMXRT1050_EVK/board.json
@@ -4,16 +4,14 @@
     ],
     "docs": "",
     "features": [
-        "Ethernet",
-        "SDRAM",
-        "MicroSD",
-        "MicroUSB",
-        "Microphone",
-        "AudioCodec",
-        "SPDIF",
+        "Audio Codec",
         "CAN",
-        "OpenSDA",
-        "JLink"
+        "Ethernet",
+        "External Flash",
+        "External RAM",
+        "Microphone",
+        "USB",
+        "microSD"
     ],
     "images": [
         "IMX_RT1050-EVKB_TOP-LR.jpg"
diff --git a/ports/mimxrt/boards/MIMXRT1050_EVK/mpconfigboard.h b/ports/mimxrt/boards/MIMXRT1050_EVK/mpconfigboard.h
index 134c9637ea..74666562a8 100644
--- a/ports/mimxrt/boards/MIMXRT1050_EVK/mpconfigboard.h
+++ b/ports/mimxrt/boards/MIMXRT1050_EVK/mpconfigboard.h
@@ -30,6 +30,16 @@
     { 0 }, { 0 }, \
     { IOMUXC_GPIO_AD_B1_10_LPUART8_TX }, { IOMUXC_GPIO_AD_B1_11_LPUART8_RX },
 
+#define IOMUX_TABLE_UART_CTS_RTS \
+    { IOMUXC_GPIO_AD_B0_14_LPUART1_CTS_B }, { IOMUXC_GPIO_AD_B0_15_LPUART1_RTS_B }, \
+    { IOMUXC_GPIO_AD_B1_00_LPUART2_CTS_B }, { IOMUXC_GPIO_AD_B1_01_LPUART2_RTS_B }, \
+    { IOMUXC_GPIO_AD_B1_04_LPUART3_CTS_B }, { IOMUXC_GPIO_AD_B1_05_LPUART3_RTS_B }, \
+    { 0 }, { 0 }, \
+    { 0 }, { 0 }, \
+    { IOMUXC_GPIO_EMC_30_LPUART6_CTS_B }, { IOMUXC_GPIO_EMC_29_LPUART6_RTS_B }, \
+    { 0 }, { 0 }, \
+    { IOMUXC_GPIO_SD_B0_02_LPUART8_CTS_B }, { IOMUXC_GPIO_SD_B0_03_LPUART8_RTS_B },
+
 #define MICROPY_HW_SPI_INDEX { 1 }
 
 #define IOMUX_TABLE_SPI \
diff --git a/ports/mimxrt/boards/MIMXRT1060_EVK/board.json b/ports/mimxrt/boards/MIMXRT1060_EVK/board.json
index 67a3818ee2..73c0cd1395 100644
--- a/ports/mimxrt/boards/MIMXRT1060_EVK/board.json
+++ b/ports/mimxrt/boards/MIMXRT1060_EVK/board.json
@@ -4,17 +4,15 @@
     ],
     "docs": "",
     "features": [
-        "Ethernet",
-        "SDRAM",
-        "MicroSD",
-        "MicroUSB",
-        "Microphone",
-        "AudioCodec",
-        "SPDIF",
+        "Audio Codec",
         "CAN",
         "Camera",
-        "OpenSDA",
-        "JLink"
+        "Ethernet",
+        "External Flash",
+        "External RAM",
+        "Microphone",
+        "USB",
+        "microSD"
     ],
     "images": [
         "X-MIMXRT1060-EVK-BOARD-BOTTOM.jpg"
diff --git a/ports/mimxrt/boards/MIMXRT1060_EVK/mpconfigboard.h b/ports/mimxrt/boards/MIMXRT1060_EVK/mpconfigboard.h
index 01ae3ba303..824f9977c2 100644
--- a/ports/mimxrt/boards/MIMXRT1060_EVK/mpconfigboard.h
+++ b/ports/mimxrt/boards/MIMXRT1060_EVK/mpconfigboard.h
@@ -30,6 +30,16 @@
     { 0 }, { 0 }, \
     { IOMUXC_GPIO_AD_B1_10_LPUART8_TX }, { IOMUXC_GPIO_AD_B1_11_LPUART8_RX },
 
+#define IOMUX_TABLE_UART_CTS_RTS \
+    { IOMUXC_GPIO_AD_B0_14_LPUART1_CTS_B }, { IOMUXC_GPIO_AD_B0_15_LPUART1_RTS_B }, \
+    { IOMUXC_GPIO_AD_B1_00_LPUART2_CTS_B }, { IOMUXC_GPIO_AD_B1_01_LPUART2_RTS_B }, \
+    { IOMUXC_GPIO_AD_B1_04_LPUART3_CTS_B }, { IOMUXC_GPIO_AD_B1_05_LPUART3_RTS_B }, \
+    { 0 }, { 0 }, \
+    { 0 }, { 0 }, \
+    { IOMUXC_GPIO_EMC_30_LPUART6_CTS_B }, { IOMUXC_GPIO_EMC_29_LPUART6_RTS_B }, \
+    { 0 }, { 0 }, \
+    { IOMUXC_GPIO_SD_B0_02_LPUART8_CTS_B }, { IOMUXC_GPIO_SD_B0_03_LPUART8_RTS_B },
+
 #define MICROPY_HW_SPI_INDEX { 1 }
 
 #define IOMUX_TABLE_SPI \
diff --git a/ports/mimxrt/boards/MIMXRT1062_af.csv b/ports/mimxrt/boards/MIMXRT1062_af.csv
index 9b83efeddc..d2f0b22023 100644
--- a/ports/mimxrt/boards/MIMXRT1062_af.csv
+++ b/ports/mimxrt/boards/MIMXRT1062_af.csv
@@ -123,3 +123,6 @@ GPIO_SD_B1_08,USDHC2_DATA4,FLEXSPI_A_DATA0,LPUART7_TXD,SAI1_TX_BCLK,LPSPI2_SOUT,
 GPIO_SD_B1_09,USDHC2_DATA5,FLEXSPI_A_DATA1,LPUART7_RXD,SAI1_TX_SYNC,LPSPI2_SIN,GPIO3_IO09,,,,,,,ALT5
 GPIO_SD_B1_10,USDHC2_DATA6,FLEXSPI_A_DATA2,LPUART2_RXD,LPI2C2_SDA,LPSPI2_PCS2,GPIO3_IO10,,,,,,,ALT5
 GPIO_SD_B1_11,USDHC2_DATA7,FLEXSPI_A_DATA3,LPUART2_TXD,LPI2C2_SCL,LPSPI2_PCS3,GPIO3_IO11,,,,,,,ALT5
+WAKEUP,,,,,,GPIO5_IO00,,NMI,,,,,ALT5
+PMIC_ON_REQ,SNVS_PMIC_ON_REQ,,,,,GPIO5_IO01,,,,,,,ALT0
+PMIC_STBY_REQ,CCM_PMIC_STBY_REQ,,,,,GPIO5_IO02,,,,,,,ALT0
diff --git a/ports/mimxrt/boards/MIMXRT1064_EVK/board.json b/ports/mimxrt/boards/MIMXRT1064_EVK/board.json
index ef12336c44..a573009d38 100644
--- a/ports/mimxrt/boards/MIMXRT1064_EVK/board.json
+++ b/ports/mimxrt/boards/MIMXRT1064_EVK/board.json
@@ -4,17 +4,15 @@
     ],
     "docs": "",
     "features": [
-        "Ethernet",
-        "SDRAM",
-        "MicroSD",
-        "MicroUSB",
-        "Microphone",
-        "AudioAmp",
-        "SPDIF",
+        "Audio Codec",
         "CAN",
         "Camera",
-        "OpenSDA",
-        "JLink"
+        "Ethernet",
+        "External Flash",
+        "External RAM",
+        "Microphone",
+        "USB",
+        "microSD"
     ],
     "images": [
         "MIMXRT1064EVK-TOP.jpg"
diff --git a/ports/mimxrt/boards/MIMXRT1064_EVK/mpconfigboard.h b/ports/mimxrt/boards/MIMXRT1064_EVK/mpconfigboard.h
index b6752c3e1b..cb64d2b9d2 100644
--- a/ports/mimxrt/boards/MIMXRT1064_EVK/mpconfigboard.h
+++ b/ports/mimxrt/boards/MIMXRT1064_EVK/mpconfigboard.h
@@ -30,6 +30,16 @@
     { 0 }, { 0 }, \
     { IOMUXC_GPIO_AD_B1_10_LPUART8_TX }, { IOMUXC_GPIO_AD_B1_11_LPUART8_RX },
 
+#define IOMUX_TABLE_UART_CTS_RTS \
+    { IOMUXC_GPIO_AD_B0_14_LPUART1_CTS_B }, { IOMUXC_GPIO_AD_B0_15_LPUART1_RTS_B }, \
+    { IOMUXC_GPIO_AD_B1_00_LPUART2_CTS_B }, { IOMUXC_GPIO_AD_B1_01_LPUART2_RTS_B }, \
+    { IOMUXC_GPIO_AD_B1_04_LPUART3_CTS_B }, { IOMUXC_GPIO_AD_B1_05_LPUART3_RTS_B }, \
+    { 0 }, { 0 }, \
+    { 0 }, { 0 }, \
+    { IOMUXC_GPIO_EMC_30_LPUART6_CTS_B }, { IOMUXC_GPIO_EMC_29_LPUART6_RTS_B }, \
+    { 0 }, { 0 }, \
+    { IOMUXC_GPIO_SD_B0_02_LPUART8_CTS_B }, { IOMUXC_GPIO_SD_B0_03_LPUART8_RTS_B },
+
 #define MICROPY_HW_SPI_INDEX { 1 }
 
 #define IOMUX_TABLE_SPI \
diff --git a/ports/mimxrt/boards/MIMXRT1170_EVK/board.json b/ports/mimxrt/boards/MIMXRT1170_EVK/board.json
index 01e554751b..73453b45a6 100644
--- a/ports/mimxrt/boards/MIMXRT1170_EVK/board.json
+++ b/ports/mimxrt/boards/MIMXRT1170_EVK/board.json
@@ -4,18 +4,15 @@
     ],
     "docs": "",
     "features": [
-        "Ethernet",
-        "SDRAM",
-        "MicroSD",
-        "MicroUSB",
-        "Microphone",
-        "AudioCodec",
-        "SPDIF",
+        "Audio Codec",
         "CAN",
         "Camera",
-        "SIM Socket",
-        "OpenSDA",
-        "JLink"
+        "Ethernet",
+        "External Flash",
+        "External RAM",
+        "Microphone",
+        "USB",
+        "microSD"
     ],
     "images": [
         "IMX-RT1170-EVK-TOP.jpg"
diff --git a/ports/mimxrt/boards/MIMXRT1170_EVK/mpconfigboard.h b/ports/mimxrt/boards/MIMXRT1170_EVK/mpconfigboard.h
index d37050eb56..8ce91adbaf 100644
--- a/ports/mimxrt/boards/MIMXRT1170_EVK/mpconfigboard.h
+++ b/ports/mimxrt/boards/MIMXRT1170_EVK/mpconfigboard.h
@@ -43,6 +43,20 @@
     { IOMUXC_GPIO_LPSR_04_LPUART11_TXD }, { IOMUXC_GPIO_LPSR_05_LPUART11_RXD }, \
     { IOMUXC_GPIO_LPSR_10_LPUART12_TXD }, { IOMUXC_GPIO_LPSR_11_LPUART12_RXD },
 
+#define IOMUX_TABLE_UART_CTS_RTS \
+    { IOMUXC_GPIO_AD_26_LPUART1_CTS_B }, { IOMUXC_GPIO_AD_27_LPUART1_RTS_B }, \
+    { IOMUXC_GPIO_DISP_B2_12_LPUART2_CTS_B }, { IOMUXC_GPIO_DISP_B2_13_LPUART2_RTS_B }, \
+    { IOMUXC_GPIO_SD_B2_07_LPUART3_CTS_B }, { IOMUXC_GPIO_SD_B2_08_LPUART3_RTS_B }, \
+    { 0 }, { 0 }, \
+    { IOMUXC_GPIO_SD_B2_09_LPUART5_CTS_B }, { IOMUXC_GPIO_SD_B2_10_LPUART5_RTS_B }, \
+    { 0 }, { 0 }, \
+    { IOMUXC_GPIO_AD_02_LPUART7_CTS_B }, { IOMUXC_GPIO_AD_03_LPUART7_RTS_B }, \
+    { IOMUXC_GPIO_AD_04_LPUART8_CTS_B }, { IOMUXC_GPIO_AD_05_LPUART8_RTS_B }, \
+    { 0 }, { 0 }, \
+    { 0 }, { 0 }, \
+    { IOMUXC_GPIO_LPSR_10_LPUART11_CTS_B }, { IOMUXC_GPIO_LPSR_11_LPUART11_RTS_B }, \
+    { IOMUXC_GPIO_LPSR_05_LPUART12_CTS_B }, { IOMUXC_GPIO_LPSR_04_LPUART12_RTS_B },
+
 // Define the mapping hardware SPI # to logical SPI #
 // SCK/CS/SDO/SDI  HW-SPI   Logical SPI
 // D13/D10/D11/D12 LPSPI1  ->  0
diff --git a/ports/mimxrt/boards/MIMXRT1176.ld b/ports/mimxrt/boards/MIMXRT1176.ld
index 2408977b94..d66c86a046 100644
--- a/ports/mimxrt/boards/MIMXRT1176.ld
+++ b/ports/mimxrt/boards/MIMXRT1176.ld
@@ -39,7 +39,7 @@ dtcm_size           = 0x00020000;
 ocrm_start          = 0x20240000;
 ocrm_size           = 0x00100000;
 
-#ifdef MICROPY_HW_SDRAM_AVAIL
+#if MICROPY_HW_SDRAM_AVAIL
 sdram_start         = 0x80000000;
 sdram_size          = MICROPY_HW_SDRAM_SIZE;
 #endif
@@ -49,7 +49,7 @@ __stack_size__ = 0x8000;
 _estack = __StackTop;
 _sstack = __StackLimit;
 
-#ifdef MICROPY_HW_SDRAM_AVAIL
+#if MICROPY_HW_SDRAM_AVAIL
 _gc_heap_start = ORIGIN(m_sdram);
 _gc_heap_end = ORIGIN(m_sdram) + LENGTH(m_sdram);
 #else
diff --git a/ports/mimxrt/boards/MIMXRT1176_af.csv b/ports/mimxrt/boards/MIMXRT1176_af.csv
index fe31f502e4..21fd2a2417 100644
--- a/ports/mimxrt/boards/MIMXRT1176_af.csv
+++ b/ports/mimxrt/boards/MIMXRT1176_af.csv
@@ -80,16 +80,16 @@ GPIO_EMC_B2_17,SEMC_DM03,XBAR1_INOUT15,ENET_1G_RX_EN,SAI3_MCLK,FLEXSPI2_A_DATA04
 GPIO_EMC_B2_18,SEMC_DQS4,XBAR1_INOUT16,ENET_1G_RX_ER,EWM_OUT_B,FLEXSPI2_A_DATA05,GPIO2_IO28,FLEXSPI1_A_DQS,,WDOG1_B,TMR3_TIMER1,GPIO8_IO28,,,
 GPIO_EMC_B2_19,SEMC_CLKX00,ENET_MDC,ENET_1G_MDC,ENET_1G_REF_CLK,FLEXSPI2_A_DATA06,GPIO2_IO29,,,ENET_QOS_MDC,TMR3_TIMER2,GPIO8_IO29,,,
 GPIO_EMC_B2_20,SEMC_CLKX01,ENET_MDIO,ENET_1G_MDIO,ENET_QOS_REF_CLK,FLEXSPI2_A_DATA07,GPIO2_IO30,,,ENET_QOS_MDIO,TMR3_TIMER3,GPIO8_IO30,,,
-GPIO_SNVS_00,SNVS_TAMPER0,,,,,GPIO13_IO03,,,,,,,,
-GPIO_SNVS_01,SNVS_TAMPER1,,,,,GPIO13_IO04,,,,,,,,
-GPIO_SNVS_02,SNVS_TAMPER2,,,,,GPIO13_IO05,,,,,,,,
-GPIO_SNVS_03,SNVS_TAMPER3,,,,,GPIO13_IO06,,,,,,,,
-GPIO_SNVS_04,SNVS_TAMPER4,,,,,GPIO13_IO07,,,,,,,,
-GPIO_SNVS_05,SNVS_TAMPER5,,,,,GPIO13_IO08,,,,,,,,
-GPIO_SNVS_06,SNVS_TAMPER6,,,,,GPIO13_IO09,,,,,,,,
-GPIO_SNVS_07,SNVS_TAMPER7,,,,,GPIO13_IO10,,,,,,,,
-GPIO_SNVS_08,SNVS_TAMPER8,,,,,GPIO13_IO11,,,,,,,,
-GPIO_SNVS_09,SNVS_TAMPER9,,,,,GPIO13_IO12,,,,,,,,
+GPIO_SNVS_00_DIG,SNVS_TAMPER0,,,,,GPIO13_IO03,,,,,,,,
+GPIO_SNVS_01_DIG,SNVS_TAMPER1,,,,,GPIO13_IO04,,,,,,,,
+GPIO_SNVS_02_DIG,SNVS_TAMPER2,,,,,GPIO13_IO05,,,,,,,,
+GPIO_SNVS_03_DIG,SNVS_TAMPER3,,,,,GPIO13_IO06,,,,,,,,
+GPIO_SNVS_04_DIG,SNVS_TAMPER4,,,,,GPIO13_IO07,,,,,,,,
+GPIO_SNVS_05_DIG,SNVS_TAMPER5,,,,,GPIO13_IO08,,,,,,,,
+GPIO_SNVS_06_DIG,SNVS_TAMPER6,,,,,GPIO13_IO09,,,,,,,,
+GPIO_SNVS_07_DIG,SNVS_TAMPER7,,,,,GPIO13_IO10,,,,,,,,
+GPIO_SNVS_08_DIG,SNVS_TAMPER8,,,,,GPIO13_IO11,,,,,,,,
+GPIO_SNVS_09_DIG,SNVS_TAMPER9,,,,,GPIO13_IO12,,,,,,,,
 GPIO_LPSR_00,FLEXCAN3_TX,MIC_CLK,MQS_RIGHT,ARM_CM4_EVENTO,,GPIO6_IO00,LPUART12_TXD,SAI4_MCLK,,,GPIO12_IO00,,,
 GPIO_LPSR_01,FLEXCAN3_RX,MIC_BITSTREAM0,MQS_LEFT,ARM_CM4_EVENTI,,GPIO6_IO01,LPUART12_RXD,,,,GPIO12_IO01,,,
 GPIO_LPSR_02,SRC_BOOT_MODE00,LPSPI5_SCK,SAI4_TX_DATA,MQS_RIGHT,,GPIO6_IO02,,,,,GPIO12_IO02,,,
diff --git a/ports/mimxrt/boards/OLIMEX_RT1010/board.json b/ports/mimxrt/boards/OLIMEX_RT1010/board.json
index 1778725658..882b931f8b 100644
--- a/ports/mimxrt/boards/OLIMEX_RT1010/board.json
+++ b/ports/mimxrt/boards/OLIMEX_RT1010/board.json
@@ -4,11 +4,9 @@
     ],
     "docs": "",
     "features": [
-        "MicroUSB",
-        "MicroSD",
-        "AudioCodec",
-        "SPDIF",
-        "JLink"
+        "External Flash",
+        "USB",
+        "microSD"
     ],
     "images": [
         "OLIMEX_RT1010Py.jpg"
diff --git a/ports/mimxrt/boards/OLIMEX_RT1010/mpconfigboard.h b/ports/mimxrt/boards/OLIMEX_RT1010/mpconfigboard.h
index 3d080ff25f..9443bb3732 100644
--- a/ports/mimxrt/boards/OLIMEX_RT1010/mpconfigboard.h
+++ b/ports/mimxrt/boards/OLIMEX_RT1010/mpconfigboard.h
@@ -25,6 +25,12 @@
     { 0 }, { 0 }, \
     { IOMUXC_GPIO_06_LPUART4_TXD }, { IOMUXC_GPIO_05_LPUART4_RXD },
 
+#define IOMUX_TABLE_UART_CTS_RTS \
+    { IOMUXC_GPIO_08_LPUART1_CTS_B }, { IOMUXC_GPIO_07_LPUART1_RTS_B }, \
+    { 0 }, { 0 }, \
+    { 0 }, { 0 }, \
+    { IOMUXC_GPIO_AD_14_LPUART4_CTS_B }, { IOMUXC_GPIO_AD_13_LPUART4_RTS_B },
+
 #define MICROPY_HW_SPI_INDEX { 0, 1, 2 }
 
 #define IOMUX_TABLE_SPI \
diff --git a/ports/mimxrt/boards/SEEED_ARCH_MIX/board.json b/ports/mimxrt/boards/SEEED_ARCH_MIX/board.json
index 3142f1a814..138d28418c 100644
--- a/ports/mimxrt/boards/SEEED_ARCH_MIX/board.json
+++ b/ports/mimxrt/boards/SEEED_ARCH_MIX/board.json
@@ -4,10 +4,11 @@
     ],
     "docs": "",
     "features": [
-        "MicroSD",
-        "MicroUSB",
-        "SDRAM",
-        "RGB LED"
+        "External Flash",
+        "External RAM",
+        "RGB LED",
+        "USB",
+        "microSD"
     ],
     "images": [
         "main1.jpg"
@@ -16,5 +17,5 @@
     "product": "Arch Mix",
     "thumbnail": "",
     "url": "https://wiki.seeedstudio.com/Arch_Mix/",
-    "vendor": "Seeed Technology Co.,Ltd."
+    "vendor": "Seeed Studio"
 }
diff --git a/ports/mimxrt/boards/SEEED_ARCH_MIX/mpconfigboard.h b/ports/mimxrt/boards/SEEED_ARCH_MIX/mpconfigboard.h
index c98cdcb0a7..edda72f266 100644
--- a/ports/mimxrt/boards/SEEED_ARCH_MIX/mpconfigboard.h
+++ b/ports/mimxrt/boards/SEEED_ARCH_MIX/mpconfigboard.h
@@ -32,6 +32,16 @@
     { 0 }, { 0 }, \
     { IOMUXC_GPIO_AD_B1_10_LPUART8_TX }, { IOMUXC_GPIO_AD_B1_11_LPUART8_RX },
 
+#define IOMUX_TABLE_UART_CTS_RTS \
+    { IOMUXC_GPIO_AD_B0_14_LPUART1_CTS_B }, { IOMUXC_GPIO_AD_B0_15_LPUART1_RTS_B }, \
+    { IOMUXC_GPIO_AD_B1_00_LPUART2_CTS_B }, { IOMUXC_GPIO_AD_B1_01_LPUART2_RTS_B }, \
+    { IOMUXC_GPIO_AD_B1_04_LPUART3_CTS_B }, { IOMUXC_GPIO_AD_B1_05_LPUART3_RTS_B }, \
+    { IOMUXC_GPIO_EMC_17_LPUART4_CTS_B }, { IOMUXC_GPIO_EMC_18_LPUART4_RTS_B }, \
+    { 0 }, { 0 }, \
+    { 0 }, { 0 }, \
+    { 0 }, { 0 }, \
+    { IOMUXC_GPIO_SD_B0_02_LPUART8_CTS_B }, { IOMUXC_GPIO_SD_B0_03_LPUART8_RTS_B },
+
 #define MICROPY_HW_SPI_INDEX { 3, 4 }
 
 #define IOMUX_TABLE_SPI \
diff --git a/ports/mimxrt/boards/TEENSY40/board.json b/ports/mimxrt/boards/TEENSY40/board.json
index daa6dbf99e..599fb2f729 100644
--- a/ports/mimxrt/boards/TEENSY40/board.json
+++ b/ports/mimxrt/boards/TEENSY40/board.json
@@ -4,7 +4,8 @@
     ],
     "docs": "",
     "features": [
-        "Breadboard Friendly"
+        "External Flash",
+        "USB"
     ],
     "images": [
         "teensy40_front.jpg"
diff --git a/ports/mimxrt/boards/TEENSY40/mpconfigboard.h b/ports/mimxrt/boards/TEENSY40/mpconfigboard.h
index 07da87db10..1a6227a60e 100644
--- a/ports/mimxrt/boards/TEENSY40/mpconfigboard.h
+++ b/ports/mimxrt/boards/TEENSY40/mpconfigboard.h
@@ -22,6 +22,16 @@
     { IOMUXC_GPIO_EMC_31_LPUART7_TX }, { IOMUXC_GPIO_EMC_32_LPUART7_RX }, \
     { IOMUXC_GPIO_AD_B1_10_LPUART8_TX }, { IOMUXC_GPIO_AD_B1_11_LPUART8_RX },
 
+#define IOMUX_TABLE_UART_CTS_RTS \
+    { IOMUXC_GPIO_AD_B0_14_LPUART1_CTS_B }, { IOMUXC_GPIO_AD_B0_15_LPUART1_RTS_B }, \
+    { IOMUXC_GPIO_AD_B1_00_LPUART2_CTS_B }, { IOMUXC_GPIO_AD_B1_01_LPUART2_RTS_B }, \
+    { IOMUXC_GPIO_AD_B1_04_LPUART3_CTS_B }, { IOMUXC_GPIO_AD_B1_05_LPUART3_RTS_B }, \
+    { IOMUXC_GPIO_EMC_17_LPUART4_CTS_B }, { IOMUXC_GPIO_EMC_18_LPUART4_RTS_B }, \
+    { 0 }, { 0 }, \
+    { IOMUXC_GPIO_EMC_30_LPUART6_CTS_B }, { IOMUXC_GPIO_EMC_29_LPUART6_RTS_B }, \
+    { IOMUXC_GPIO_SD_B1_06_LPUART7_CTS_B }, { IOMUXC_GPIO_SD_B1_07_LPUART7_RTS_B }, \
+    { IOMUXC_GPIO_SD_B0_02_LPUART8_CTS_B }, { IOMUXC_GPIO_SD_B0_03_LPUART8_RTS_B },
+
 #define MICROPY_HW_SPI_INDEX { 4, 3}
 
 #define IOMUX_TABLE_SPI \
diff --git a/ports/mimxrt/boards/TEENSY41/board.json b/ports/mimxrt/boards/TEENSY41/board.json
index 1f8fe37a99..08235d4dae 100644
--- a/ports/mimxrt/boards/TEENSY41/board.json
+++ b/ports/mimxrt/boards/TEENSY41/board.json
@@ -4,9 +4,10 @@
     ],
     "docs": "",
     "features": [
-        "MicroSD",
         "Ethernet",
-        "Breadboard Friendly"
+        "External Flash",
+        "USB",
+        "microSD"
     ],
     "images": [
         "teensy41_4.jpg"
diff --git a/ports/mimxrt/boards/TEENSY41/mpconfigboard.h b/ports/mimxrt/boards/TEENSY41/mpconfigboard.h
index 56740f48ea..09addbe52c 100644
--- a/ports/mimxrt/boards/TEENSY41/mpconfigboard.h
+++ b/ports/mimxrt/boards/TEENSY41/mpconfigboard.h
@@ -24,6 +24,16 @@
     { IOMUXC_GPIO_EMC_31_LPUART7_TX }, { IOMUXC_GPIO_EMC_32_LPUART7_RX }, \
     { IOMUXC_GPIO_AD_B1_10_LPUART8_TX }, { IOMUXC_GPIO_AD_B1_11_LPUART8_RX },
 
+#define IOMUX_TABLE_UART_CTS_RTS \
+    { IOMUXC_GPIO_AD_B0_14_LPUART1_CTS_B }, { IOMUXC_GPIO_AD_B0_15_LPUART1_RTS_B }, \
+    { IOMUXC_GPIO_AD_B1_00_LPUART2_CTS_B }, { IOMUXC_GPIO_AD_B1_01_LPUART2_RTS_B }, \
+    { IOMUXC_GPIO_AD_B1_04_LPUART3_CTS_B }, { IOMUXC_GPIO_AD_B1_05_LPUART3_RTS_B }, \
+    { IOMUXC_GPIO_EMC_17_LPUART4_CTS_B }, { IOMUXC_GPIO_EMC_18_LPUART4_RTS_B }, \
+    { IOMUXC_GPIO_EMC_28_LPUART5_CTS_B }, { IOMUXC_GPIO_EMC_27_LPUART5_RTS_B }, \
+    { IOMUXC_GPIO_EMC_30_LPUART6_CTS_B }, { IOMUXC_GPIO_EMC_29_LPUART6_RTS_B }, \
+    { IOMUXC_GPIO_SD_B1_06_LPUART7_CTS_B }, { IOMUXC_GPIO_SD_B1_07_LPUART7_RTS_B }, \
+    { IOMUXC_GPIO_SD_B0_02_LPUART8_CTS_B }, { IOMUXC_GPIO_SD_B0_03_LPUART8_RTS_B },
+
 #define MICROPY_HW_SPI_INDEX { 4, 3, 1 }
 
 #define IOMUX_TABLE_SPI \
diff --git a/ports/mimxrt/boards/make-pins.py b/ports/mimxrt/boards/make-pins.py
index 429d648696..51ae9eb717 100644
--- a/ports/mimxrt/boards/make-pins.py
+++ b/ports/mimxrt/boards/make-pins.py
@@ -24,6 +24,10 @@ regexes = [
     r"IOMUXC_(?P<pin>GPIO_EMC_B\d_\d\d)_(?P<function>\w+) (?P<muxRegister>\w+), (?P<muxMode>\w+), (?P<inputRegister>\w+), (?P<inputDaisy>\w+), (?P<configRegister>\w+)",
     r"IOMUXC_(?P<pin>GPIO_DISP_B\d_\d\d)_(?P<function>\w+) (?P<muxRegister>\w+), (?P<muxMode>\w+), (?P<inputRegister>\w+), (?P<inputDaisy>\w+), (?P<configRegister>\w+)",
     r"IOMUXC_(?P<pin>GPIO_LPSR_\d\d)_(?P<function>\w+) (?P<muxRegister>\w+), (?P<muxMode>\w+), (?P<inputRegister>\w+), (?P<inputDaisy>\w+), (?P<configRegister>\w+)",
+    r"IOMUXC_[SNVS_]*(?P<pin>WAKEUP[_DIG]*)_(?P<function>\w+) (?P<muxRegister>\w+), (?P<muxMode>\w+), (?P<inputRegister>\w+), (?P<inputDaisy>\w+), (?P<configRegister>\w+)",
+    r"IOMUXC_SNVS_(?P<pin>PMIC_ON_REQ)_(?P<function>\w+) (?P<muxRegister>\w+), (?P<muxMode>\w+), (?P<inputRegister>\w+), (?P<inputDaisy>\w+), (?P<configRegister>\w+)",
+    r"IOMUXC_SNVS_(?P<pin>PMIC_STBY_REQ)_(?P<function>\w+) (?P<muxRegister>\w+), (?P<muxMode>\w+), (?P<inputRegister>\w+), (?P<inputDaisy>\w+), (?P<configRegister>\w+)",
+    r"IOMUXC_(?P<pin>GPIO_SNVS_\d\d_DIG)_(?P<function>\w+) (?P<muxRegister>\w+), (?P<muxMode>\w+), (?P<inputRegister>\w+), (?P<inputDaisy>\w+), (?P<configRegister>\w+)",
 ]
 
 
@@ -118,10 +122,43 @@ class Pin(object):
             self.print_pin_af()
             self.print_pin_adc()
 
+            options = {
+                "GPIO_LPSR_00": "PIN_LPSR",
+                "GPIO_LPSR_01": "PIN_LPSR",
+                "GPIO_LPSR_02": "PIN_LPSR",
+                "GPIO_LPSR_03": "PIN_LPSR",
+                "GPIO_LPSR_04": "PIN_LPSR",
+                "GPIO_LPSR_05": "PIN_LPSR",
+                "GPIO_LPSR_06": "PIN_LPSR",
+                "GPIO_LPSR_07": "PIN_LPSR",
+                "GPIO_LPSR_08": "PIN_LPSR",
+                "GPIO_LPSR_09": "PIN_LPSR",
+                "GPIO_LPSR_10": "PIN_LPSR",
+                "GPIO_LPSR_11": "PIN_LPSR",
+                "GPIO_LPSR_12": "PIN_LPSR",
+                "GPIO_LPSR_13": "PIN_LPSR",
+                "GPIO_LPSR_14": "PIN_LPSR",
+                "GPIO_LPSR_15": "PIN_LPSR",
+                "GPIO_SNVS_00_DIG": "PIN_SNVS",
+                "GPIO_SNVS_01_DIG": "PIN_SNVS",
+                "GPIO_SNVS_02_DIG": "PIN_SNVS",
+                "GPIO_SNVS_03_DIG": "PIN_SNVS",
+                "GPIO_SNVS_04_DIG": "PIN_SNVS",
+                "GPIO_SNVS_05_DIG": "PIN_SNVS",
+                "GPIO_SNVS_06_DIG": "PIN_SNVS",
+                "GPIO_SNVS_07_DIG": "PIN_SNVS",
+                "GPIO_SNVS_08_DIG": "PIN_SNVS",
+                "GPIO_SNVS_09_DIG": "PIN_SNVS",
+                "WAKEUP": "PIN_SNVS",
+                "WAKEUP_DIG": "PIN_SNVS",
+                "PMIC_ON_REQ": "PIN_SNVS",
+                "PMIC_STBY_REQ": "PIN_SNVS",
+            }
+
             print(
                 "const machine_pin_obj_t pin_{0} = {1}({0}, {2}, {3}, pin_{0}_af, {4}, {5});\n".format(
                     self.name,
-                    "PIN_LPSR" if "LPSR" in self.name else "PIN",
+                    options.get(self.name, "PIN"),
                     self.gpio,
                     int(self.pin),
                     len(self.adc_fns),
@@ -233,9 +270,6 @@ class Pins(object):
                 pin_number = pin.lstrip("IO")
                 pin = Pin(pad, gpio, pin_number, idx=idx)
 
-                if any(s in pad for s in ("SNVS", "WAKEUP")):
-                    continue
-
                 # Parse alternate functions
                 af_idx = 0
                 for af_idx, af in enumerate(row[(pad_col + 1) : adc_col]):
diff --git a/ports/mimxrt/boards/mimxrt_prefix.c b/ports/mimxrt/boards/mimxrt_prefix.c
index 09c0aa109e..d7a2bcfc80 100644
--- a/ports/mimxrt/boards/mimxrt_prefix.c
+++ b/ports/mimxrt/boards/mimxrt_prefix.c
@@ -49,3 +49,17 @@
         .adc_list = (_adc_list), \
     } \
 
+#define PIN_SNVS(_name, _gpio, _pin, _af_list, _adc_list_len, _adc_list) \
+    { \
+        .base = { &machine_pin_type }, \
+        .name = MP_QSTR_##_name, \
+        .gpio = (_gpio), \
+        .pin = (uint32_t)(_pin), \
+        .muxRegister = (uint32_t)&(IOMUXC_SNVS->SW_MUX_CTL_PAD_##_name), \
+        .configRegister = (uint32_t)&(IOMUXC_SNVS->SW_PAD_CTL_PAD_##_name), \
+        .af_list_len = (uint8_t)(sizeof((_af_list)) / sizeof(machine_pin_af_obj_t)), \
+        .adc_list_len = (_adc_list_len), \
+        .af_list = (_af_list), \
+        .adc_list = (_adc_list), \
+    } \
+
diff --git a/ports/mimxrt/cyw43_configport.h b/ports/mimxrt/cyw43_configport.h
new file mode 100644
index 0000000000..5f96856474
--- /dev/null
+++ b/ports/mimxrt/cyw43_configport.h
@@ -0,0 +1,155 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2022 Damien P. George
+ * Copyright (c) 2022 Jim Mussared
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+#ifndef MICROPY_INCLUDED_STM32_CYW43_CONFIGPORT_H
+#define MICROPY_INCLUDED_STM32_CYW43_CONFIGPORT_H
+
+// The board-level config will be included here, so it can set some CYW43 values.
+#include "py/mpconfig.h"
+#include "py/mperrno.h"
+#include "py/mphal.h"
+#include "extmod/modnetwork.h"
+#include "pendsv.h"
+#include "sdio.h"
+
+#define CYW43_USE_SPI                   (0)
+#define CYW43_LWIP                      (1)
+#define CYW43_USE_STATS                 (0)
+
+#ifndef CYW43_CHIPSET_FIRMWARE_INCLUDE_FILE
+#define CYW43_CHIPSET_FIRMWARE_INCLUDE_FILE "lib/cyw43-driver/firmware/w4343WA1_7_45_98_50_combined.h"
+#endif
+
+#ifndef CYW43_WIFI_NVRAM_INCLUDE_FILE
+#define CYW43_WIFI_NVRAM_INCLUDE_FILE   "lib/cyw43-driver/firmware/wifi_nvram_1dx.h"
+#endif
+
+#define CYW43_IOCTL_TIMEOUT_US          (1000000)
+#define CYW43_SLEEP_MAX                 (50)
+#define CYW43_NETUTILS                  (1)
+#define CYW43_CLEAR_SDIO_INT            (1)
+
+#define CYW43_EPERM                     MP_EPERM // Operation not permitted
+#define CYW43_EIO                       MP_EIO // I/O error
+#define CYW43_EINVAL                    MP_EINVAL // Invalid argument
+#define CYW43_ETIMEDOUT                 MP_ETIMEDOUT // Connection timed out
+
+#define CYW43_THREAD_ENTER              MICROPY_PY_LWIP_ENTER
+#define CYW43_THREAD_EXIT               MICROPY_PY_LWIP_EXIT
+#define CYW43_THREAD_LOCK_CHECK
+
+#define CYW43_HOST_NAME                 mod_network_hostname
+
+#define CYW43_SDPCM_SEND_COMMON_WAIT    __WFI();
+#define CYW43_DO_IOCTL_WAIT             __WFI();
+
+#define CYW43_ARRAY_SIZE(a)             MP_ARRAY_SIZE(a)
+
+#define CYW43_HAL_PIN_MODE_INPUT        MP_HAL_PIN_MODE_INPUT
+#define CYW43_HAL_PIN_MODE_OUTPUT       MP_HAL_PIN_MODE_OUTPUT
+#define CYW43_HAL_PIN_PULL_NONE         MP_HAL_PIN_PULL_NONE
+#define CYW43_HAL_PIN_PULL_UP           MP_HAL_PIN_PULL_UP
+#define CYW43_HAL_PIN_PULL_DOWN         MP_HAL_PIN_PULL_DOWN
+
+#define CYW43_HAL_MAC_WLAN0             MP_HAL_MAC_WLAN0
+
+#define cyw43_hal_ticks_us              mp_hal_ticks_us
+#define cyw43_hal_ticks_ms              mp_hal_ticks_ms
+
+#define cyw43_hal_pin_obj_t             mp_hal_pin_obj_t
+#define cyw43_hal_pin_read              mp_hal_pin_read
+#define cyw43_hal_pin_low               mp_hal_pin_low
+#define cyw43_hal_pin_high              mp_hal_pin_high
+
+#define cyw43_hal_get_mac               mp_hal_get_mac
+#define cyw43_hal_get_mac_ascii         mp_hal_get_mac_ascii
+#define cyw43_hal_generate_laa_mac      mp_hal_generate_laa_mac
+
+#define cyw43_delay_us                  mp_hal_delay_us
+#define cyw43_delay_ms                  mp_hal_delay_ms
+
+#define CYW43_PIN_WL_REG_ON             MICROPY_HW_WL_REG_ON
+#define CYW43_PIN_WL_HOST_WAKE          MICROPY_HW_WL_HOST_WAKE
+#define CYW43_PIN_WL_SDIO_1             MICROPY_HW_SDIO_D1
+
+#define CYW43_PIN_BT_REG_ON             MICROPY_HW_BT_REG_ON
+#ifdef MICROPY_HW_BT_HOST_WAKE
+#define CYW43_PIN_BT_HOST_WAKE          MICROPY_HW_BT_HOST_WAKE
+#endif
+#ifdef MICROPY_HW_BT_DEV_WAKE
+#define CYW43_PIN_BT_DEV_WAKE           MICROPY_HW_BT_DEV_WAKE
+#endif
+#ifdef MICROPY_HW_BT_CTS
+#define CYW43_PIN_BT_CTS                MICROPY_HW_BT_CTS
+#endif
+
+#if MICROPY_HW_ENABLE_RF_SWITCH
+#define CYW43_PIN_WL_RFSW_VDD           pin_WL_RFSW_VDD
+#endif
+
+#define cyw43_schedule_internal_poll_dispatch(func) pendsv_schedule_dispatch(PENDSV_DISPATCH_CYW43, func)
+
+static inline void cyw43_hal_pin_config(cyw43_hal_pin_obj_t pin, uint8_t mode, uint8_t pull, uint8_t alt) {
+    machine_pin_set_mode(pin, mode);
+}
+
+static inline void cyw43_hal_pin_config_irq_falling(cyw43_hal_pin_obj_t pin, int enable) {
+    if (enable) {
+        machine_pin_config(pin, PIN_MODE_IT_FALLING, PIN_PULL_UP_100K, 0, 0, PIN_AF_MODE_ALT5);
+    }
+}
+
+static inline void cyw43_sdio_init(void) {
+    sdio_init(NVIC_EncodePriority(NVIC_PRIORITYGROUP_4, 14, 0));
+}
+
+static inline void cyw43_sdio_reinit(void) {
+    sdio_reenable();
+}
+
+static inline void cyw43_sdio_deinit(void) {
+    sdio_deinit();
+}
+
+static inline void cyw43_sdio_set_irq(bool enable) {
+    sdio_enable_irq(enable);
+}
+
+static inline void cyw43_sdio_enable_high_speed_4bit(void) {
+    sdio_enable_high_speed_4bit();
+}
+
+static inline int cyw43_sdio_transfer(uint32_t cmd, uint32_t arg, uint32_t *resp) {
+    return sdio_transfer(cmd, arg, resp);
+}
+
+static inline int cyw43_sdio_transfer_cmd53(bool write, uint32_t block_size, uint32_t arg, size_t len, uint8_t *buf) {
+    return sdio_transfer_cmd53(write, block_size, arg, len, buf);
+}
+
+#define CYW43_EVENT_POLL_HOOK MICROPY_EVENT_POLL_HOOK
+
+#endif // MICROPY_INCLUDED_STM32_CYW43_CONFIGPORT_H
diff --git a/ports/mimxrt/hal/pwm_backport.c b/ports/mimxrt/hal/pwm_backport.c
index 018f8f6279..7732e0e816 100644
--- a/ports/mimxrt/hal/pwm_backport.c
+++ b/ports/mimxrt/hal/pwm_backport.c
@@ -18,10 +18,10 @@
 #include "hal/pwm_backport.h"
 
 void PWM_UpdatePwmDutycycle_u16(
-    PWM_Type *base, pwm_submodule_t subModule, pwm_channels_t pwmSignal, uint16_t dutyCycle, uint16_t Center_u16) {
+    PWM_Type *base, pwm_submodule_t subModule, pwm_channels_t pwmSignal, uint32_t dutyCycle, uint16_t Center_u16) {
     assert((uint16_t)pwmSignal < 2U);
-    uint16_t pulseCnt = 0, pwmHighPulse = 0;
-    uint16_t center;
+    uint32_t pulseCnt = 0, pwmHighPulse = 0;
+    uint32_t center;
 
     // check and confine bounds for Center_u16
     if ((Center_u16 + dutyCycle / 2) >= PWM_FULL_SCALE) {
@@ -36,11 +36,21 @@ void PWM_UpdatePwmDutycycle_u16(
 
     // Setup the PWM dutycycle of channel A or B
     if (pwmSignal == kPWM_PwmA) {
-        base->SM[subModule].VAL2 = center - pwmHighPulse / 2;
-        base->SM[subModule].VAL3 = base->SM[subModule].VAL2 + pwmHighPulse;
+        if (dutyCycle >= 65536) {
+            base->SM[subModule].VAL2 = 0;
+            base->SM[subModule].VAL3 = pulseCnt;
+        } else {
+            base->SM[subModule].VAL2 = center - pwmHighPulse / 2;
+            base->SM[subModule].VAL3 = base->SM[subModule].VAL2 + pwmHighPulse;
+        }
     } else {
-        base->SM[subModule].VAL4 = center - pwmHighPulse / 2;
-        base->SM[subModule].VAL5 = base->SM[subModule].VAL4 + pwmHighPulse;
+        if (dutyCycle >= 65536) {
+            base->SM[subModule].VAL4 = 0;
+            base->SM[subModule].VAL5 = pulseCnt;
+        } else {
+            base->SM[subModule].VAL4 = center - pwmHighPulse / 2;
+            base->SM[subModule].VAL5 = base->SM[subModule].VAL4 + pwmHighPulse;
+        }
     }
 }
 
@@ -86,33 +96,33 @@ void PWM_SetupPwm_u16(PWM_Type *base, pwm_submodule_t subModule, pwm_signal_para
 }
 
 void PWM_SetupPwmx_u16(PWM_Type *base, pwm_submodule_t subModule,
-    uint32_t pwmFreq_Hz, uint16_t duty_cycle, uint8_t invert, uint32_t srcClock_Hz) {
+    uint32_t pwmFreq_Hz, uint32_t duty_cycle, uint8_t invert, uint32_t srcClock_Hz) {
 
     uint32_t pulseCnt;
     uint32_t pwmClock;
 
     // Divide the clock by the prescale value
     pwmClock = (srcClock_Hz / (1U << ((base->SM[subModule].CTRL & PWM_CTRL_PRSC_MASK) >> PWM_CTRL_PRSC_SHIFT)));
-    pulseCnt = (pwmClock + (pwmFreq_Hz - 1) / 2) / pwmFreq_Hz;
+    pulseCnt = (pwmClock + (pwmFreq_Hz - 1) / 2) / pwmFreq_Hz - 1;
     base->SM[subModule].INIT = 0;
-    base->SM[subModule].VAL0 = ((uint32_t)duty_cycle * pulseCnt) / PWM_FULL_SCALE - 1;
-    base->SM[subModule].VAL1 = pulseCnt - 1;
+    base->SM[subModule].VAL0 = ((uint32_t)duty_cycle * pulseCnt) / PWM_FULL_SCALE;
+    base->SM[subModule].VAL1 = pulseCnt;
 
     base->SM[subModule].OCTRL = (base->SM[subModule].OCTRL & ~PWM_OCTRL_POLX_MASK) | PWM_OCTRL_POLX(!invert);
 
-    base->OUTEN |= (1U << subModule);
+    // Switch the output on or off.
+    if (duty_cycle == 0) {
+        base->OUTEN &= ~(1U << subModule);
+    } else {
+        base->OUTEN |= (1U << subModule);
+    }
 }
 
 #ifdef FSL_FEATURE_SOC_TMR_COUNT
 status_t QTMR_SetupPwm_u16(TMR_Type *base, qtmr_channel_selection_t channel, uint32_t pwmFreqHz,
-    uint16_t dutyCycleU16, bool outputPolarity, uint32_t srcClock_Hz, bool is_init) {
+    uint32_t dutyCycleU16, bool outputPolarity, uint32_t srcClock_Hz, bool is_init) {
     uint32_t periodCount, highCount, lowCount, reg;
 
-    if (dutyCycleU16 >= PWM_FULL_SCALE) {
-        // Invalid dutycycle
-        return kStatus_Fail;
-    }
-
     // Counter values to generate a PWM signal
     periodCount = ((srcClock_Hz + (pwmFreqHz - 1) / 2) / pwmFreqHz) - 2;
     highCount = (periodCount * dutyCycleU16) / PWM_FULL_SCALE;
@@ -147,11 +157,18 @@ status_t QTMR_SetupPwm_u16(TMR_Type *base, qtmr_channel_selection_t channel, uin
 
     reg = base->CHANNEL[channel].CTRL;
     reg &= ~(TMR_CTRL_OUTMODE_MASK);
-    // Count until compare value is  reached and re-initialize the counter, toggle OFLAG output
-    // using alternating compare register
-    reg |= (TMR_CTRL_LENGTH_MASK | TMR_CTRL_OUTMODE(kQTMR_ToggleOnAltCompareReg));
+    if (dutyCycleU16 == 0) {
+        // Clear the output at the next compare
+        reg |= (TMR_CTRL_LENGTH_MASK | TMR_CTRL_OUTMODE(kQTMR_ClearOnCompare));
+    } else if (dutyCycleU16 >= 65536) {
+        // Set the output at the next compare
+        reg |= (TMR_CTRL_LENGTH_MASK | TMR_CTRL_OUTMODE(kQTMR_SetOnCompare));
+    } else {
+        // Count until compare value is  reached and re-initialize the counter, toggle OFLAG output
+        // using alternating compare register
+        reg |= (TMR_CTRL_LENGTH_MASK | TMR_CTRL_OUTMODE(kQTMR_ToggleOnAltCompareReg));
+    }
     base->CHANNEL[channel].CTRL = reg;
-
     return kStatus_Success;
 }
 #endif // FSL_FEATURE_SOC_TMR_COUNT
diff --git a/ports/mimxrt/hal/pwm_backport.h b/ports/mimxrt/hal/pwm_backport.h
index 516726961c..04899173e2 100644
--- a/ports/mimxrt/hal/pwm_backport.h
+++ b/ports/mimxrt/hal/pwm_backport.h
@@ -18,7 +18,7 @@
 typedef struct _pwm_signal_param_u16
 {
     pwm_channels_t pwmChannel; // PWM channel being configured; PWM A or PWM B
-    uint16_t dutyCycle_u16;    // PWM pulse width, value should be between 0 to 65536
+    uint32_t dutyCycle_u16;    // PWM pulse width, value should be between 0 to 65536
     uint16_t Center_u16;       // Center of the pulse, value should be between 0 to 65536
     pwm_level_select_t level;  // PWM output active level select */
     uint16_t deadtimeValue;    // The deadtime value; only used if channel pair is operating in complementary mode
@@ -27,17 +27,17 @@ typedef struct _pwm_signal_param_u16
 #define PWM_FULL_SCALE  (65536UL)
 
 void PWM_UpdatePwmDutycycle_u16(PWM_Type *base, pwm_submodule_t subModule,
-    pwm_channels_t pwmSignal, uint16_t dutyCycle, uint16_t center);
+    pwm_channels_t pwmSignal, uint32_t dutyCycle, uint16_t center);
 
 void PWM_SetupPwm_u16(PWM_Type *base, pwm_submodule_t subModule, pwm_signal_param_u16_t *chnlParams,
     uint32_t pwmFreq_Hz, uint32_t srcClock_Hz, bool output_enable);
 
 void PWM_SetupPwmx_u16(PWM_Type *base, pwm_submodule_t subModule,
-    uint32_t pwmFreq_Hz, uint16_t duty_cycle, uint8_t invert, uint32_t srcClock_Hz);
+    uint32_t pwmFreq_Hz, uint32_t duty_cycle, uint8_t invert, uint32_t srcClock_Hz);
 
 #ifdef FSL_FEATURE_SOC_TMR_COUNT
 status_t QTMR_SetupPwm_u16(TMR_Type *base, qtmr_channel_selection_t channel, uint32_t pwmFreqHz,
-    uint16_t dutyCycleU16, bool outputPolarity, uint32_t srcClock_Hz, bool is_init);
+    uint32_t dutyCycleU16, bool outputPolarity, uint32_t srcClock_Hz, bool is_init);
 #endif // FSL_FEATURE_SOC_TMR_COUNT
 
 #endif // PWM_BACKPORT_H
diff --git a/ports/mimxrt/hal/qspi_hyper_flash_config.c b/ports/mimxrt/hal/qspi_hyper_flash_config.c
index f5ffbe8413..aaf2e923c1 100644
--- a/ports/mimxrt/hal/qspi_hyper_flash_config.c
+++ b/ports/mimxrt/hal/qspi_hyper_flash_config.c
@@ -22,6 +22,10 @@ __attribute__((section(".boot_hdr.conf")))
 #pragma location = ".boot_hdr.conf"
 #endif
 
+#ifndef MICROPY_HW_FLASH_CLK
+#define MICROPY_HW_FLASH_CLK kFlexSpiSerialClk_133MHz
+#endif
+
 const flexspi_nor_config_t qspiflash_config = {
     .memConfig =
     {
@@ -36,7 +40,7 @@ const flexspi_nor_config_t qspiflash_config = {
             (1u << kFlexSpiMiscOffset_DdrModeEnable) | (1u << kFlexSpiMiscOffset_WordAddressableEnable) |
             (1u << kFlexSpiMiscOffset_SafeConfigFreqEnable) | (1u << kFlexSpiMiscOffset_DiffClkEnable),
         .sflashPadType = kSerialFlash_8Pads,
-        .serialClkFreq = kFlexSpiSerialClk_133MHz,
+        .serialClkFreq = MICROPY_HW_FLASH_CLK,
         .sflashA1Size = MICROPY_HW_FLASH_SIZE,
         .dataValidTime = {16u, 16u},
         .lookupTable =
diff --git a/ports/mimxrt/hal/qspi_nor_flash_config.c b/ports/mimxrt/hal/qspi_nor_flash_config.c
index a6bbd624ed..a8040737e5 100644
--- a/ports/mimxrt/hal/qspi_nor_flash_config.c
+++ b/ports/mimxrt/hal/qspi_nor_flash_config.c
@@ -28,6 +28,10 @@ __attribute__((section(".boot_hdr.conf")))
 #define MICROPY_HW_FLASH_DQS kFlexSPIReadSampleClk_LoopbackFromDqsPad
 #endif
 
+#ifndef MICROPY_HW_FLASH_CLK
+#define MICROPY_HW_FLASH_CLK kFlexSpiSerialClk_100MHz
+#endif
+
 const flexspi_nor_config_t qspiflash_config = {
     .memConfig =
     {
@@ -48,7 +52,7 @@ const flexspi_nor_config_t qspiflash_config = {
         // Enable DDR mode, Wordaddassable, Safe configuration, Differential clock
         .deviceType = kFlexSpiDeviceType_SerialNOR,
         .sflashPadType = kSerialFlash_4Pads,
-        .serialClkFreq = kFlexSpiSerialClk_100MHz,
+        .serialClkFreq = MICROPY_HW_FLASH_CLK,
         .sflashA1Size = MICROPY_HW_FLASH_SIZE,
         .lookupTable =
         {
diff --git a/ports/mimxrt/irq.h b/ports/mimxrt/irq.h
new file mode 100644
index 0000000000..b83eb49ffa
--- /dev/null
+++ b/ports/mimxrt/irq.h
@@ -0,0 +1,80 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2023 Damien P. George
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+#ifndef MICROPY_INCLUDED_MIMXRT_IRQ_H
+#define MICROPY_INCLUDED_MIMXRT_IRQ_H
+
+#define NVIC_PRIORITYGROUP_4    ((uint32_t)0x00000003)
+
+static inline uint32_t query_irq(void) {
+    return __get_PRIMASK();
+}
+
+static inline uint32_t raise_irq_pri(uint32_t pri) {
+    uint32_t basepri = __get_BASEPRI();
+    // If non-zero, the processor does not process any exception with a
+    // priority value greater than or equal to BASEPRI.
+    // When writing to BASEPRI_MAX the write goes to BASEPRI only if either:
+    //   - Rn is non-zero and the current BASEPRI value is 0
+    //   - Rn is non-zero and less than the current BASEPRI value
+    pri <<= (8 - __NVIC_PRIO_BITS);
+    __ASM volatile ("msr basepri_max, %0" : : "r" (pri) : "memory");
+    return basepri;
+}
+
+// "basepri" should be the value returned from raise_irq_pri
+static inline void restore_irq_pri(uint32_t basepri) {
+    __set_BASEPRI(basepri);
+}
+
+// IRQ priority definitions.
+//
+// Lower number implies higher interrupt priority.
+//
+// The default priority grouping used in this port is NVIC_PRIORITYGROUP_4.
+// This corresponds to 4 bits for the priority field and 0 bits for the
+// sub-priority field (which means that for all intents and purposes the
+// sub-priorities below are ignored).
+//
+// While a given interrupt is being processed, only higher priority (lower number)
+// interrupts will preempt a given interrupt. If sub-priorities are active
+// then the sub-priority determines the order that pending interrupts of
+// a given priority are executed. This is only meaningful if 2 or more
+// interrupts of the same priority are pending at the same time.
+//
+// The following interrupts are arranged from highest priority to lowest
+// priority to make it a bit easier to figure out.
+
+#define IRQ_PRI_SYSTICK         NVIC_EncodePriority(NVIC_PRIORITYGROUP_4, 0, 0)
+
+#define IRQ_PRI_OTG_HS          NVIC_EncodePriority(NVIC_PRIORITYGROUP_4, 6, 0)
+
+#define IRQ_PRI_EXTINT          NVIC_EncodePriority(NVIC_PRIORITYGROUP_4, 14, 0)
+
+// PENDSV should be at the lowst priority so that other interrupts complete
+// before exception is raised.
+#define IRQ_PRI_PENDSV          NVIC_EncodePriority(NVIC_PRIORITYGROUP_4, 15, 0)
+
+#endif // MICROPY_INCLUDED_MIMXRT_IRQ_H
diff --git a/ports/mimxrt/machine_pin.c b/ports/mimxrt/machine_pin.c
index f005e38d69..3ebccb1755 100644
--- a/ports/mimxrt/machine_pin.c
+++ b/ports/mimxrt/machine_pin.c
@@ -34,6 +34,9 @@
 #include "shared/runtime/mpirq.h"
 #include "extmod/virtpin.h"
 #include "pin.h"
+#if MICROPY_PY_NETWORK_CYW43
+#include "pendsv.h"
+#endif
 
 // Local functions
 STATIC mp_obj_t machine_pin_obj_init_helper(const machine_pin_obj_t *self, size_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args);
@@ -98,6 +101,16 @@ void call_handler(GPIO_Type *gpio, int gpio_nr, int pin) {
         if (isr & mask) {
             gpio->ISR = mask; // clear the ISR flag
             int index = GET_PIN_IRQ_INDEX(gpio_nr, pin);
+            #if MICROPY_PY_NETWORK_CYW43
+            extern void (*cyw43_poll)(void);
+            const machine_pin_obj_t *pin = MICROPY_HW_WL_HOST_WAKE;
+            if (pin->gpio == gpio && pin->pin == (index % 32)) {
+                if (cyw43_poll) {
+                    pendsv_schedule_dispatch(PENDSV_DISPATCH_CYW43, cyw43_poll);
+                }
+                return;
+            }
+            #endif
             machine_pin_irq_obj_t *irq = MP_STATE_PORT(machine_pin_irq_objects[index]);
             if (irq != NULL) {
                 irq->flags = irq->trigger;
@@ -187,6 +200,60 @@ void machine_pin_set_mode(const machine_pin_obj_t *self, uint8_t mode) {
     GPIO_PinInit(self->gpio, self->pin, &pin_config);
 }
 
+void machine_pin_config(const machine_pin_obj_t *self, uint8_t mode,
+    uint8_t pull, uint8_t drive, uint8_t speed, uint8_t alt) {
+    (void)speed;
+    gpio_pin_config_t pin_config = {0};
+
+    if (IS_GPIO_IT_MODE(mode)) {
+        if (mode == PIN_MODE_IT_FALLING) {
+            pin_config.interruptMode = kGPIO_IntFallingEdge;
+        } else if (mode == PIN_MODE_IT_RISING) {
+            pin_config.interruptMode = kGPIO_IntRisingEdge;
+        } else if (mode == PIN_MODE_IT_BOTH) {
+            pin_config.interruptMode = kGPIO_IntRisingOrFallingEdge;
+        }
+        // Set pad config mode to input.
+        mode = PIN_MODE_IN;
+    }
+
+    if (mode == PIN_MODE_IN) {
+        pin_config.direction = kGPIO_DigitalInput;
+    } else {
+        pin_config.direction = kGPIO_DigitalOutput;
+    }
+
+    if (mode != PIN_MODE_ALT) {
+        // GPIO is always ALT5
+        alt = PIN_AF_MODE_ALT5;
+    }
+
+    const machine_pin_af_obj_t *af = pin_find_af(self, alt);
+    if (af == NULL) {
+        return;
+    }
+
+    // Configure the pad.
+    uint32_t pad_config = pin_generate_config(pull, mode, drive, self->configRegister);
+    IOMUXC_SetPinMux(self->muxRegister, alt, af->input_register, af->input_daisy, self->configRegister, 0U);
+    IOMUXC_SetPinConfig(self->muxRegister, alt, af->input_register, af->input_daisy, self->configRegister, pad_config);
+
+    // Initialize the pin.
+    GPIO_PinInit(self->gpio, self->pin, &pin_config);
+
+    // Configure interrupt (if enabled).
+    if (pin_config.interruptMode != kGPIO_NoIntmode) {
+        uint32_t gpio_nr = GPIO_get_instance(self->gpio);
+        uint32_t irq_num = self->pin < 16 ? GPIO_combined_low_irqs[gpio_nr] : GPIO_combined_high_irqs[gpio_nr];
+
+        GPIO_PortEnableInterrupts(self->gpio, 1U << self->pin);
+        GPIO_PortClearInterruptFlags(self->gpio, ~0);
+
+        NVIC_SetPriority(irq_num, IRQ_PRI_EXTINT);
+        EnableIRQ(irq_num);
+    }
+}
+
 STATIC mp_obj_t machine_pin_obj_call(mp_obj_t self_in, mp_uint_t n_args, mp_uint_t n_kw, const mp_obj_t *args) {
     mp_arg_check_num(n_args, n_kw, 0, 1, false);
     machine_pin_obj_t *self = self_in;
@@ -337,6 +404,13 @@ STATIC mp_obj_t machine_pin_irq(size_t n_args, const mp_obj_t *pos_args, mp_map_
     }
     machine_pin_irq_obj_t *irq = MP_STATE_PORT(machine_pin_irq_objects[index]);
 
+    if (args[ARG_handler].u_obj == mp_const_none) {
+        // remove the IRQ from the table, leave it to gc to free it.
+        GPIO_PortDisableInterrupts(self->gpio, 1U << self->pin);
+        MP_STATE_PORT(machine_pin_irq_objects[index]) = NULL;
+        return mp_const_none;
+    }
+
     // Allocate the IRQ object if it doesn't already exist.
     if (irq == NULL) {
         irq = m_new_obj(machine_pin_irq_obj_t);
@@ -371,9 +445,9 @@ STATIC mp_obj_t machine_pin_irq(size_t n_args, const mp_obj_t *pos_args, mp_map_
             GPIO_PinSetInterruptConfig(self->gpio, self->pin, irq->trigger);
             // Enable the specific Pin interrupt
             GPIO_PortEnableInterrupts(self->gpio, 1U << self->pin);
+            // Enable LEVEL1 interrupt again
+            EnableIRQ(irq_num);
         }
-        // Enable LEVEL1 interrupt again
-        EnableIRQ(irq_num);
     }
 
     return MP_OBJ_FROM_PTR(irq);
diff --git a/ports/mimxrt/machine_uart.c b/ports/mimxrt/machine_uart.c
index ac9351da8a..fba2b7fe30 100644
--- a/ports/mimxrt/machine_uart.c
+++ b/ports/mimxrt/machine_uart.c
@@ -33,6 +33,7 @@
 #include "fsl_lpuart.h"
 #include "fsl_iomuxc.h"
 #include CLOCK_CONFIG_H
+#include "modmachine.h"
 #include "pin.h"
 
 #define DEFAULT_UART_BAUDRATE (115200)
@@ -40,6 +41,10 @@
 #define MIN_BUFFER_SIZE  (32)
 #define MAX_BUFFER_SIZE  (32766)
 
+#define UART_HWCONTROL_RTS  (1)
+#define UART_HWCONTROL_CTS  (2)
+#define UART_HWCONTROL_MASK (UART_HWCONTROL_RTS | UART_HWCONTROL_CTS)
+
 #define UART_INVERT_TX (1)
 #define UART_INVERT_RX (2)
 #define UART_INVERT_MASK (UART_INVERT_TX | UART_INVERT_RX)
@@ -74,12 +79,18 @@ STATIC LPUART_Type *uart_base_ptr_table[] = LPUART_BASE_PTRS;
 static const iomux_table_t iomux_table_uart[] = {
     IOMUX_TABLE_UART
 };
+static const iomux_table_t iomux_table_uart_cts_rts[] = {
+    IOMUX_TABLE_UART_CTS_RTS
+};
 
 STATIC const char *_parity_name[] = {"None", "", "0", "1"};  // Is defined as 0, 2, 3
 STATIC const char *_invert_name[] = {"None", "INV_TX", "INV_RX", "INV_TX|INV_RX"};
+STATIC const char *_flow_name[] = {"None", "RTS", "CTS", "RTS|CTS"};
 
 #define RX (iomux_table_uart[index + 1])
 #define TX (iomux_table_uart[index])
+#define RTS (iomux_table_uart_cts_rts[index + 1])
+#define CTS (iomux_table_uart_cts_rts[index])
 
 bool lpuart_set_iomux(int8_t uart) {
     int index = (uart - 1) * 2;
@@ -98,6 +109,33 @@ bool lpuart_set_iomux(int8_t uart) {
     }
 }
 
+bool lpuart_set_iomux_rts(int8_t uart) {
+    MP_STATIC_ASSERT(MP_ARRAY_SIZE(iomux_table_uart) == MP_ARRAY_SIZE(iomux_table_uart_cts_rts));
+    int index = (uart - 1) * 2;
+
+    if (RTS.muxRegister != 0) {
+        IOMUXC_SetPinMux(RTS.muxRegister, RTS.muxMode, RTS.inputRegister, RTS.inputDaisy, RTS.configRegister, 0U);
+        IOMUXC_SetPinConfig(RTS.muxRegister, RTS.muxMode, RTS.inputRegister, RTS.inputDaisy, RTS.configRegister,
+            pin_generate_config(PIN_PULL_UP_100K, PIN_MODE_OUT, PIN_DRIVE_6, RTS.configRegister));
+        return true;
+    } else {
+        return false;
+    }
+}
+
+bool lpuart_set_iomux_cts(int8_t uart) {
+    int index = (uart - 1) * 2;
+
+    if (CTS.muxRegister != 0) {
+        IOMUXC_SetPinMux(CTS.muxRegister, CTS.muxMode, CTS.inputRegister, CTS.inputDaisy, CTS.configRegister, 0U);
+        IOMUXC_SetPinConfig(CTS.muxRegister, CTS.muxMode, CTS.inputRegister, CTS.inputDaisy, CTS.configRegister,
+            pin_generate_config(PIN_PULL_UP_100K, PIN_MODE_IN, PIN_DRIVE_6, CTS.configRegister));
+        return true;
+    } else {
+        return false;
+    }
+}
+
 void LPUART_UserCallback(LPUART_Type *base, lpuart_handle_t *handle, status_t status, void *userData) {
     machine_uart_obj_t *self = userData;
     if (kStatus_LPUART_TxIdle == status) {
@@ -109,24 +147,54 @@ void LPUART_UserCallback(LPUART_Type *base, lpuart_handle_t *handle, status_t st
     }
 }
 
+static void machine_uart_ensure_active(machine_uart_obj_t *uart) {
+    if (uart->lpuart->CTRL == 0) {
+        mp_raise_OSError(EIO);
+    }
+}
+
+#if !defined(MIMXRT117x_SERIES)
+static inline void uart_set_clock_divider(uint32_t baudrate) {
+    // For baud rates < 460800 divide the clock by 10, supporting baud rates down to 50 baud.
+    if (baudrate >= 460800) {
+        CLOCK_SetDiv(kCLOCK_UartDiv, 0);
+    } else {
+        CLOCK_SetDiv(kCLOCK_UartDiv, 9);
+    }
+}
+#endif
+
+void machine_uart_set_baudrate(mp_obj_t uart_in, uint32_t baudrate) {
+    machine_uart_obj_t *uart = MP_OBJ_TO_PTR(uart_in);
+    #if defined(MIMXRT117x_SERIES)
+    // Use the Lpuart1 clock value, which is set for All UART devices.
+    LPUART_SetBaudRate(uart->lpuart, baudrate, CLOCK_GetRootClockFreq(kCLOCK_Root_Lpuart1));
+    #else
+    uart_set_clock_divider(baudrate);
+    LPUART_SetBaudRate(uart->lpuart, baudrate, CLOCK_GetClockRootFreq(kCLOCK_UartClkRoot));
+    #endif
+}
+
 STATIC void machine_uart_print(const mp_print_t *print, mp_obj_t self_in, mp_print_kind_t kind) {
     machine_uart_obj_t *self = MP_OBJ_TO_PTR(self_in);
-    mp_printf(print, "UART(%u, baudrate=%u, bits=%u, parity=%s, stop=%u, "
+    mp_printf(print, "UART(%u, baudrate=%u, bits=%u, parity=%s, stop=%u, flow=%s, "
         "rxbuf=%d, txbuf=%d, timeout=%u, timeout_char=%u, invert=%s)",
         self->id, self->config.baudRate_Bps, 8 - self->config.dataBitsCount,
         _parity_name[self->config.parityMode], self->config.stopBitCount + 1,
+        _flow_name[(self->config.enableTxCTS << 1) | self->config.enableRxRTS],
         self->handle.rxRingBufferSize, self->txbuf_len, self->timeout, self->timeout_char,
         _invert_name[self->invert]);
 }
 
 STATIC mp_obj_t machine_uart_init_helper(machine_uart_obj_t *self, size_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
-    enum { ARG_baudrate, ARG_bits, ARG_parity, ARG_stop,
+    enum { ARG_baudrate, ARG_bits, ARG_parity, ARG_stop, ARG_flow,
            ARG_timeout, ARG_timeout_char, ARG_invert, ARG_rxbuf, ARG_txbuf};
     static const mp_arg_t allowed_args[] = {
         { MP_QSTR_baudrate, MP_ARG_INT, {.u_int = -1} },
         { MP_QSTR_bits, MP_ARG_INT, {.u_int = -1} },
         { MP_QSTR_parity, MP_ARG_OBJ, {.u_rom_obj = MP_ROM_INT(-1)} },
         { MP_QSTR_stop, MP_ARG_INT, {.u_int = -1} },
+        { MP_QSTR_flow, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = -1 } },
         { MP_QSTR_timeout, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = -1} },
         { MP_QSTR_timeout_char, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = -1} },
         { MP_QSTR_invert, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = -1} },
@@ -164,6 +232,27 @@ STATIC mp_obj_t machine_uart_init_helper(machine_uart_obj_t *self, size_t n_args
         self->config.stopBitCount = args[ARG_stop].u_int - 1;
     }
 
+    // Set flow if configured.
+    if (args[ARG_flow].u_int >= 0) {
+        if (args[ARG_flow].u_int & ~UART_HWCONTROL_MASK) {
+            mp_raise_ValueError(MP_ERROR_TEXT("bad flow mask"));
+        }
+
+        if (args[ARG_flow].u_int & UART_HWCONTROL_RTS) {
+            if (!lpuart_set_iomux_rts(uart_index_table[self->id])) {
+                mp_raise_ValueError(MP_ERROR_TEXT("rts not available"));
+            }
+            self->config.enableRxRTS = true;
+        }
+
+        if (args[ARG_flow].u_int & UART_HWCONTROL_CTS) {
+            if (!lpuart_set_iomux_cts(uart_index_table[self->id])) {
+                mp_raise_ValueError(MP_ERROR_TEXT("cts not available"));
+            }
+            self->config.enableTxCTS = true;
+        }
+    }
+
     // Set timeout if configured.
     if (args[ARG_timeout].u_int >= 0) {
         self->timeout = args[ARG_timeout].u_int;
@@ -222,7 +311,13 @@ STATIC mp_obj_t machine_uart_init_helper(machine_uart_obj_t *self, size_t n_args
             self->timeout_char = min_timeout_char;
         }
 
-        LPUART_Init(self->lpuart, &self->config, BOARD_BOOTCLOCKRUN_UART_CLK_ROOT);
+        #if defined(MIMXRT117x_SERIES)
+        // Use the Lpuart1 clock value, which is set for All UART devices.
+        LPUART_Init(self->lpuart, &self->config, CLOCK_GetRootClockFreq(kCLOCK_Root_Lpuart1));
+        #else
+        uart_set_clock_divider(self->config.baudRate_Bps);
+        LPUART_Init(self->lpuart, &self->config, CLOCK_GetClockRootFreq(kCLOCK_UartClkRoot));
+        #endif
         LPUART_TransferCreateHandle(self->lpuart, &self->handle,  LPUART_UserCallback, self);
         uint8_t *buffer = m_new(uint8_t, rxbuf_len + 1);
         LPUART_TransferStartRingBuffer(self->lpuart, &self->handle, buffer, rxbuf_len);
@@ -288,8 +383,17 @@ STATIC mp_obj_t machine_uart_init(size_t n_args, const mp_obj_t *args, mp_map_t
 }
 MP_DEFINE_CONST_FUN_OBJ_KW(machine_uart_init_obj, 1, machine_uart_init);
 
+// uart.deinit()
+STATIC mp_obj_t machine_uart_deinit(mp_obj_t self_in) {
+    machine_uart_obj_t *self = MP_OBJ_TO_PTR(self_in);
+    LPUART_SoftwareReset(self->lpuart);
+    return mp_const_none;
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_1(machine_uart_deinit_obj, machine_uart_deinit);
+
 STATIC mp_obj_t machine_uart_any(mp_obj_t self_in) {
     machine_uart_obj_t *self = MP_OBJ_TO_PTR(self_in);
+    machine_uart_ensure_active(self);
     size_t count = LPUART_TransferGetRxRingBufferLength(self->lpuart, &self->handle);
     return MP_OBJ_NEW_SMALL_INT(count);
 }
@@ -297,6 +401,7 @@ STATIC MP_DEFINE_CONST_FUN_OBJ_1(machine_uart_any_obj, machine_uart_any);
 
 STATIC mp_obj_t machine_uart_sendbreak(mp_obj_t self_in) {
     machine_uart_obj_t *self = MP_OBJ_TO_PTR(self_in);
+    machine_uart_ensure_active(self);
     self->lpuart->CTRL |= 1 << LPUART_CTRL_SBK_SHIFT; // Set SBK bit
     self->lpuart->CTRL &= ~LPUART_CTRL_SBK_MASK; // Clear SBK bit
     return mp_const_none;
@@ -314,8 +419,18 @@ STATIC mp_obj_t machine_uart_txdone(mp_obj_t self_in) {
 }
 STATIC MP_DEFINE_CONST_FUN_OBJ_1(machine_uart_txdone_obj, machine_uart_txdone);
 
+// Reset all defined UARTs
+void machine_uart_deinit_all(void) {
+    for (int i = 0; i < MICROPY_HW_UART_NUM; i++) {
+        if (uart_index_table[i] != 0) {
+            LPUART_SoftwareReset(uart_base_ptr_table[uart_index_table[i]]);
+        }
+    }
+}
+
 STATIC const mp_rom_map_elem_t machine_uart_locals_dict_table[] = {
     { MP_ROM_QSTR(MP_QSTR_init), MP_ROM_PTR(&machine_uart_init_obj) },
+    { MP_ROM_QSTR(MP_QSTR_deinit), MP_ROM_PTR(&machine_uart_deinit_obj) },
 
     { MP_ROM_QSTR(MP_QSTR_any), MP_ROM_PTR(&machine_uart_any_obj) },
 
@@ -328,6 +443,9 @@ STATIC const mp_rom_map_elem_t machine_uart_locals_dict_table[] = {
     { MP_ROM_QSTR(MP_QSTR_sendbreak), MP_ROM_PTR(&machine_uart_sendbreak_obj) },
     { MP_ROM_QSTR(MP_QSTR_txdone), MP_ROM_PTR(&machine_uart_txdone_obj) },
 
+    { MP_ROM_QSTR(MP_QSTR_RTS), MP_ROM_INT(UART_HWCONTROL_RTS) },
+    { MP_ROM_QSTR(MP_QSTR_CTS), MP_ROM_INT(UART_HWCONTROL_CTS) },
+
     { MP_ROM_QSTR(MP_QSTR_INV_TX), MP_ROM_INT(UART_INVERT_TX) },
     { MP_ROM_QSTR(MP_QSTR_INV_RX), MP_ROM_INT(UART_INVERT_RX) },
 
@@ -343,6 +461,8 @@ STATIC mp_uint_t machine_uart_read(mp_obj_t self_in, void *buf_in, mp_uint_t siz
     size_t avail;
     size_t nget;
 
+    machine_uart_ensure_active(self);
+
     for (size_t received = 0; received < size;) {
         // Wait for the first/next character.
         while ((avail = LPUART_TransferGetRxRingBufferLength(self->lpuart, &self->handle)) <= 0) {
@@ -375,6 +495,8 @@ STATIC mp_uint_t machine_uart_write(mp_obj_t self_in, const void *buf_in, mp_uin
     size_t offset = 0;
     uint8_t fifo_size = FSL_FEATURE_LPUART_FIFO_SIZEn(0);
 
+    machine_uart_ensure_active(self);
+
     // First check if a previous transfer is still ongoing,
     // then wait at least the number of remaining character times.
     t = ticks_us64() + (uint64_t)(self->handle.txDataSize + fifo_size) * (13000000 / self->config.baudRate_Bps + 1000);
@@ -429,6 +551,7 @@ STATIC mp_uint_t machine_uart_ioctl(mp_obj_t self_in, mp_uint_t request, mp_uint
     machine_uart_obj_t *self = self_in;
     mp_uint_t ret;
     if (request == MP_STREAM_POLL) {
+        machine_uart_ensure_active(self);
         uintptr_t flags = arg;
         ret = 0;
         if (flags & MP_STREAM_POLL_RD) {
diff --git a/ports/mimxrt/main.c b/ports/mimxrt/main.c
index 9ac46e4814..993e598185 100644
--- a/ports/mimxrt/main.c
+++ b/ports/mimxrt/main.c
@@ -43,7 +43,16 @@
 #if MICROPY_PY_LWIP
 #include "lwip/init.h"
 #include "lwip/apps/mdns.h"
+#if MICROPY_PY_NETWORK_CYW43
+#include "lib/cyw43-driver/src/cyw43.h"
 #endif
+#endif
+
+#if MICROPY_PY_BLUETOOTH
+#include "mpbthciport.h"
+#include "extmod/modbluetooth.h"
+#endif
+
 #include "systick.h"
 #include "extmod/modnetwork.h"
 
@@ -68,6 +77,20 @@ int main(void) {
 
     systick_enable_dispatch(SYSTICK_DISPATCH_LWIP, mod_network_lwip_poll_wrapper);
     #endif
+    #if MICROPY_PY_BLUETOOTH
+    mp_bluetooth_hci_init();
+    #endif
+
+    #if MICROPY_PY_NETWORK_CYW43
+    {
+        cyw43_init(&cyw43_state);
+        uint8_t buf[8];
+        memcpy(&buf[0], "PYBD", 4);
+        mp_hal_get_mac_ascii(MP_HAL_MAC_WLAN0, 8, 4, (char *)&buf[4]);
+        cyw43_wifi_ap_set_ssid(&cyw43_state, 8, buf);
+        cyw43_wifi_ap_set_password(&cyw43_state, 8, (const uint8_t *)"pybd0123");
+    }
+    #endif
 
     for (;;) {
         #if defined(MICROPY_HW_LED1)
@@ -121,9 +144,13 @@ int main(void) {
         #if MICROPY_PY_MACHINE_I2S
         machine_i2s_deinit_all();
         #endif
+        #if MICROPY_PY_BLUETOOTH
+        mp_bluetooth_deinit();
+        #endif
         #if MICROPY_PY_NETWORK
         mod_network_deinit();
         #endif
+        machine_uart_deinit_all();
         machine_pwm_deinit_all();
         soft_timer_deinit();
         gc_sweep_all();
diff --git a/ports/mimxrt/modmachine.h b/ports/mimxrt/modmachine.h
index ed1c4e34a0..904419df2c 100644
--- a/ports/mimxrt/modmachine.h
+++ b/ports/mimxrt/modmachine.h
@@ -43,6 +43,7 @@ extern const mp_obj_type_t machine_wdt_type;
 void machine_adc_init(void);
 void machine_pin_irq_deinit(void);
 void machine_pwm_deinit_all(void);
+void machine_uart_deinit_all(void);
 void machine_timer_init_PIT(void);
 void machine_sdcard_init0(void);
 void mimxrt_sdram_init(void);
@@ -50,4 +51,6 @@ void machine_i2s_init0();
 void machine_i2s_deinit_all(void);
 void machine_rtc_start(void);
 
+void machine_uart_set_baudrate(mp_obj_t uart, uint32_t baudrate);
+
 #endif // MICROPY_INCLUDED_MIMXRT_MODMACHINE_H
diff --git a/ports/mimxrt/mpbthciport.c b/ports/mimxrt/mpbthciport.c
new file mode 100644
index 0000000000..d8b3841364
--- /dev/null
+++ b/ports/mimxrt/mpbthciport.c
@@ -0,0 +1,191 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2018-2021 Damien P. George
+ * Copyright (c) 2023 Ibrahim Abdelkader <iabdalkader@openmv.io>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include "py/runtime.h"
+#include "py/stream.h"
+#include "py/mphal.h"
+#include "extmod/modbluetooth.h"
+#include "extmod/mpbthci.h"
+#include "shared/runtime/softtimer.h"
+#include "modmachine.h"
+#include "mpbthciport.h"
+
+#if MICROPY_PY_BLUETOOTH
+
+#define DEBUG_printf(...) // mp_printf(&mp_plat_print, "mpbthciport.c: " __VA_ARGS__)
+#define ERROR_printf(...) mp_printf(&mp_plat_print, "mpbthciport.c: " __VA_ARGS__)
+
+uint8_t mp_bluetooth_hci_cmd_buf[4 + 256];
+
+STATIC mp_sched_node_t mp_bluetooth_hci_sched_node;
+STATIC soft_timer_entry_t mp_bluetooth_hci_soft_timer;
+
+STATIC void mp_bluetooth_hci_soft_timer_callback(soft_timer_entry_t *self) {
+    mp_bluetooth_hci_poll_now();
+}
+
+void mp_bluetooth_hci_init(void) {
+    soft_timer_static_init(
+        &mp_bluetooth_hci_soft_timer,
+        SOFT_TIMER_MODE_ONE_SHOT,
+        0,
+        mp_bluetooth_hci_soft_timer_callback
+        );
+}
+
+STATIC void mp_bluetooth_hci_start_polling(void) {
+    mp_bluetooth_hci_poll_now();
+}
+
+void mp_bluetooth_hci_poll_in_ms(uint32_t ms) {
+    soft_timer_reinsert(&mp_bluetooth_hci_soft_timer, ms);
+}
+
+// For synchronous mode, we run all BLE stack code inside a scheduled task.
+STATIC void run_events_scheduled_task(mp_sched_node_t *node) {
+    // This will process all buffered HCI UART data, and run any callouts or events.
+    mp_bluetooth_hci_poll();
+}
+
+// Called periodically (systick) or directly (e.g. UART RX IRQ) in order to
+// request that processing happens ASAP in the scheduler.
+void mp_bluetooth_hci_poll_now(void) {
+    mp_sched_schedule_node(&mp_bluetooth_hci_sched_node, run_events_scheduled_task);
+}
+
+mp_obj_t mp_bthci_uart;
+
+int mp_bluetooth_hci_uart_init(uint32_t port, uint32_t baudrate) {
+    DEBUG_printf("mp_bluetooth_hci_uart_init\n");
+
+    mp_obj_t args[] = {
+        MP_OBJ_NEW_SMALL_INT(port),
+        MP_OBJ_NEW_QSTR(MP_QSTR_baudrate), MP_OBJ_NEW_SMALL_INT(baudrate),
+        MP_OBJ_NEW_QSTR(MP_QSTR_timeout), MP_OBJ_NEW_SMALL_INT(200),
+        MP_OBJ_NEW_QSTR(MP_QSTR_timeout_char), MP_OBJ_NEW_SMALL_INT(200),
+        MP_OBJ_NEW_QSTR(MP_QSTR_txbuf), MP_OBJ_NEW_SMALL_INT(768),
+        MP_OBJ_NEW_QSTR(MP_QSTR_rxbuf), MP_OBJ_NEW_SMALL_INT(768),
+    };
+
+    mp_bthci_uart = MP_OBJ_TYPE_GET_SLOT(&machine_uart_type, make_new)((mp_obj_t)&machine_uart_type, 1, 5, args);
+    MP_STATE_PORT(mp_bthci_uart) = mp_bthci_uart;
+
+    // Start the HCI polling to process any initial events/packets.
+    mp_bluetooth_hci_start_polling();
+    return 0;
+}
+
+int mp_bluetooth_hci_uart_deinit(void) {
+    DEBUG_printf("mp_bluetooth_hci_uart_deinit\n");
+    mp_bthci_uart = MP_OBJ_NULL;
+    return 0;
+}
+
+int mp_bluetooth_hci_uart_set_baudrate(uint32_t baudrate) {
+    DEBUG_printf("mp_bluetooth_hci_uart_set_baudrate(%lu)\n", baudrate);
+    if (mp_bthci_uart != MP_OBJ_NULL) {
+        machine_uart_set_baudrate(mp_bthci_uart, baudrate);
+    }
+    return 0;
+}
+
+int mp_bluetooth_hci_uart_any(void) {
+    int errcode = 0;
+    const mp_stream_p_t *proto = (mp_stream_p_t *)MP_OBJ_TYPE_GET_SLOT(&machine_uart_type, protocol);
+
+    mp_uint_t ret = proto->ioctl(mp_bthci_uart, MP_STREAM_POLL, MP_STREAM_POLL_RD, &errcode);
+    if (errcode != 0) {
+        ERROR_printf("Uart ioctl failed to poll UART %d\n", errcode);
+        return -1;
+    }
+    return ret & MP_STREAM_POLL_RD;
+}
+
+int mp_bluetooth_hci_uart_write(const uint8_t *buf, size_t len) {
+    DEBUG_printf("mp_bluetooth_hci_uart_write\n");
+
+    int errcode = 0;
+    const mp_stream_p_t *proto = (mp_stream_p_t *)MP_OBJ_TYPE_GET_SLOT(&machine_uart_type, protocol);
+
+    mp_bluetooth_hci_controller_wakeup();
+
+    if (proto->write(mp_bthci_uart, (void *)buf, len, &errcode) < 0) {
+        ERROR_printf("mp_bluetooth_hci_uart_write: failed to write to UART %d\n", errcode);
+    }
+    return 0;
+}
+
+// This function expects the controller to be in the wake state via a previous call
+// to mp_bluetooth_hci_controller_woken.
+int mp_bluetooth_hci_uart_readchar(void) {
+    DEBUG_printf("mp_bluetooth_hci_uart_readchar\n");
+    if (mp_bluetooth_hci_uart_any()) {
+        int errcode = 0;
+        uint8_t buf = 0;
+        const mp_stream_p_t *proto = (mp_stream_p_t *)MP_OBJ_TYPE_GET_SLOT(&machine_uart_type, protocol);
+        if (proto->read(mp_bthci_uart, (void *)&buf, 1, &errcode) < 0) {
+            ERROR_printf("mp_bluetooth_hci_uart_readchar: failed to read UART %d\n", errcode);
+            return -1;
+        }
+        return buf;
+    } else {
+        DEBUG_printf("mp_bluetooth_hci_uart_readchar: not ready\n");
+        return -1;
+    }
+}
+
+// Default (weak) implementation of the HCI controller interface.
+// A driver (e.g. cywbt43.c) can override these for controller-specific
+// functionality (i.e. power management).
+MP_WEAK int mp_bluetooth_hci_controller_init(void) {
+    DEBUG_printf("mp_bluetooth_hci_controller_init (default)\n");
+    return 0;
+}
+
+MP_WEAK int mp_bluetooth_hci_controller_deinit(void) {
+    DEBUG_printf("mp_bluetooth_hci_controller_deinit (default)\n");
+    return 0;
+}
+
+MP_WEAK int mp_bluetooth_hci_controller_sleep_maybe(void) {
+    DEBUG_printf("mp_bluetooth_hci_controller_sleep_maybe (default)\n");
+    return 0;
+}
+
+MP_WEAK bool mp_bluetooth_hci_controller_woken(void) {
+    DEBUG_printf("mp_bluetooth_hci_controller_woken (default)\n");
+    return true;
+}
+
+MP_WEAK int mp_bluetooth_hci_controller_wakeup(void) {
+    DEBUG_printf("mp_bluetooth_hci_controller_wakeup (default)\n");
+    return 0;
+}
+
+MP_REGISTER_ROOT_POINTER(mp_obj_t mp_bthci_uart);
+
+#endif // MICROPY_PY_BLUETOOTH
diff --git a/ports/mimxrt/mpbthciport.h b/ports/mimxrt/mpbthciport.h
new file mode 100644
index 0000000000..124c85dae5
--- /dev/null
+++ b/ports/mimxrt/mpbthciport.h
@@ -0,0 +1,42 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2018-2021 Damien P. George
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+#ifndef MICROPY_INCLUDED_MIMXRT_MPBTHCIPORT_H
+#define MICROPY_INCLUDED_MIMXRT_MPBTHCIPORT_H
+
+// Initialise the HCI subsystem (should be called once, early on).
+void mp_bluetooth_hci_init(void);
+
+// Poll the HCI now, or after a certain timeout.
+void mp_bluetooth_hci_poll_now(void);
+void mp_bluetooth_hci_poll_in_ms(uint32_t ms);
+
+// Must be provided by the stack bindings (e.g. mpnimbleport.c or mpbtstackport.c).
+// Request new data from the uart and pass to the stack, and run pending events/callouts.
+// This is a low-level function and should not be called directly, use
+// mp_bluetooth_hci_poll_now/mp_bluetooth_hci_poll_in_ms instead.
+void mp_bluetooth_hci_poll(void);
+
+#endif // MICROPY_INCLUDED_MIMXRT_MPBTHCIPORT_H
diff --git a/ports/mimxrt/mpconfigport.h b/ports/mimxrt/mpconfigport.h
index 52054c5d4d..fb4acede59 100644
--- a/ports/mimxrt/mpconfigport.h
+++ b/ports/mimxrt/mpconfigport.h
@@ -59,6 +59,7 @@ uint32_t trng_random_u32(void);
 #define MICROPY_ENABLE_EMERGENCY_EXCEPTION_BUF  (1)
 #define MICROPY_LONGINT_IMPL                (MICROPY_LONGINT_IMPL_MPZ)
 #define MICROPY_SCHEDULER_DEPTH             (8)
+#define MICROPY_SCHEDULER_STATIC_NODES      (1)
 #define MICROPY_VFS                         (1)
 
 // Control over Python builtins
@@ -67,7 +68,6 @@ uint32_t trng_random_u32(void);
 
 // Extended modules
 #define MICROPY_EPOCH_IS_1970               (1)
-#define MICROPY_PY_SSL_FINALISER            (MICROPY_PY_SSL)
 #define MICROPY_PY_TIME_GMTIME_LOCALTIME_MKTIME (1)
 #define MICROPY_PY_TIME_TIME_TIME_NS        (1)
 #define MICROPY_PY_TIME_INCLUDEFILE         "ports/mimxrt/modtime.c"
@@ -110,7 +110,6 @@ uint32_t trng_random_u32(void);
 #define MICROPY_PY_WEBSOCKET                (MICROPY_PY_LWIP)
 #define MICROPY_PY_WEBREPL                  (MICROPY_PY_LWIP)
 #define MICROPY_PY_LWIP_SOCK_RAW            (MICROPY_PY_LWIP)
-#define MICROPY_PY_SSL_FINALISER            (MICROPY_PY_SSL)
 // #define MICROPY_PY_HASHLIB_MD5              (MICROPY_PY_SSL)
 #define MICROPY_PY_HASHLIB_SHA1             (MICROPY_PY_SSL)
 // #define MICROPY_PY_CRYPTOLIB                (MICROPY_PY_SSL)
@@ -120,6 +119,14 @@ uint32_t trng_random_u32(void);
 #define MICROPY_PY_LWIP_REENTER MICROPY_PY_PENDSV_REENTER
 #define MICROPY_PY_LWIP_EXIT    MICROPY_PY_PENDSV_EXIT
 
+#ifndef MICROPY_PY_BLUETOOTH_ENABLE_CENTRAL_MODE
+#define MICROPY_PY_BLUETOOTH_ENABLE_CENTRAL_MODE (1)
+#endif
+
+#ifndef MICROPY_PY_BLUETOOTH_ENABLE_L2CAP_CHANNELS
+#define MICROPY_PY_BLUETOOTH_ENABLE_L2CAP_CHANNELS (MICROPY_BLUETOOTH_NIMBLE)
+#endif
+
 #ifndef MICROPY_PY_NETWORK_HOSTNAME_DEFAULT
 #define MICROPY_PY_NETWORK_HOSTNAME_DEFAULT "mpy-mimxrt"
 #endif
@@ -145,23 +152,6 @@ __attribute__((always_inline)) static inline uint32_t disable_irq(void) {
     return state;
 }
 
-static inline uint32_t raise_irq_pri(uint32_t pri) {
-    uint32_t basepri = __get_BASEPRI();
-    // If non-zero, the processor does not process any exception with a
-    // priority value greater than or equal to BASEPRI.
-    // When writing to BASEPRI_MAX the write goes to BASEPRI only if either:
-    //   - Rn is non-zero and the current BASEPRI value is 0
-    //   - Rn is non-zero and less than the current BASEPRI value
-    pri <<= (8 - __NVIC_PRIO_BITS);
-    __ASM volatile ("msr basepri_max, %0" : : "r" (pri) : "memory");
-    return basepri;
-}
-
-// "basepri" should be the value returned from raise_irq_pri
-static inline void restore_irq_pri(uint32_t basepri) {
-    __set_BASEPRI(basepri);
-}
-
 #define MICROPY_BEGIN_ATOMIC_SECTION()     disable_irq()
 #define MICROPY_END_ATOMIC_SECTION(state)  enable_irq(state)
 
@@ -172,12 +162,20 @@ extern const struct _mp_obj_type_t network_lan_type;
 #define MICROPY_HW_NIC_ETH
 #endif
 
+#if MICROPY_PY_NETWORK_CYW43
+extern const struct _mp_obj_type_t mp_network_cyw43_type;
+#define MICROPY_HW_NIC_CYW43                { MP_ROM_QSTR(MP_QSTR_WLAN), MP_ROM_PTR(&mp_network_cyw43_type) },
+#else
+#define MICROPY_HW_NIC_CYW43
+#endif
+
 #ifndef MICROPY_BOARD_NETWORK_INTERFACES
 #define MICROPY_BOARD_NETWORK_INTERFACES
 #endif
 
 #define MICROPY_PORT_NETWORK_INTERFACES \
     MICROPY_HW_NIC_ETH  \
+    MICROPY_HW_NIC_CYW43 \
     MICROPY_BOARD_NETWORK_INTERFACES \
 
 #ifndef MICROPY_BOARD_ROOT_POINTERS
diff --git a/ports/mimxrt/mphalport.h b/ports/mimxrt/mphalport.h
index ba7e1cfa94..36eb387798 100644
--- a/ports/mimxrt/mphalport.h
+++ b/ports/mimxrt/mphalport.h
@@ -31,6 +31,7 @@
 #include "ticks.h"
 #include "py/ringbuf.h"
 #include "pin.h"
+#include "irq.h"
 #include "fsl_clock.h"
 
 #define MICROPY_HAL_VERSION             "2.8.0"
@@ -38,6 +39,25 @@
 #define MICROPY_HW_USB_CDC_TX_TIMEOUT   (500)
 
 #define MP_HAL_PIN_FMT                  "%q"
+#define MP_HAL_PIN_MODE_INPUT           PIN_MODE_IN
+#define MP_HAL_PIN_MODE_OUTPUT          PIN_MODE_OUT
+#define MP_HAL_PIN_MODE_ALT             PIN_MODE_ALT
+#define MP_HAL_PIN_MODE_OPEN_DRAIN      PIN_MODE_OPEN_DRAIN
+
+#define MP_HAL_PIN_PULL_NONE            PIN_PULL_DISABLED
+#define MP_HAL_PIN_PULL_UP              PIN_PULL_UP_100K
+#define MP_HAL_PIN_PULL_DOWN            PIN_PULL_DOWN_100K
+
+#define MP_HAL_PIN_SPEED_LOW            (0)
+#define MP_HAL_PIN_SPEED_MEDIUM         (1)
+#define MP_HAL_PIN_SPEED_HIGH           (2)
+#define MP_HAL_PIN_SPEED_VERY_HIGH      (3)
+
+#define MP_HAL_PIN_TRIGGER_NONE         kGPIO_NoIntmode
+#define MP_HAL_PIN_TRIGGER_FALL         kGPIO_IntFallingEdge
+#define MP_HAL_PIN_TRIGGER_RISE         kGPIO_IntRisingEdge
+#define MP_HAL_PIN_TRIGGER_RISE_FALL    kGPIO_IntRisingOrFallingEdge
+
 extern ringbuf_t stdin_ringbuf;
 
 // Define an alias for systick_ms, because the shared softtimer.c uses
diff --git a/ports/mimxrt/mpnetworkport.c b/ports/mimxrt/mpnetworkport.c
index 2e6a49b90e..2ca3426197 100644
--- a/ports/mimxrt/mpnetworkport.c
+++ b/ports/mimxrt/mpnetworkport.c
@@ -43,6 +43,11 @@
 #include "lwip/dhcp.h"
 #include "lwip/apps/mdns.h"
 
+#if MICROPY_PY_NETWORK_CYW43
+#include "extmod/network_cyw43.h"
+#include "lib/cyw43-driver/src/cyw43.h"
+#endif
+
 // Poll lwIP every 128ms
 #define LWIP_TICK(tick) (((tick) & ~(SYSTICK_DISPATCH_NUM_SLOTS - 1) & 0x7f) == 0)
 
@@ -59,6 +64,16 @@ void mod_network_lwip_poll_wrapper(uint32_t ticks_ms) {
     if (LWIP_TICK(ticks_ms)) {
         pendsv_schedule_dispatch(PENDSV_DISPATCH_LWIP, pyb_lwip_poll);
     }
+
+    #if MICROPY_PY_NETWORK_CYW43
+    if (cyw43_poll) {
+        if (cyw43_sleep != 0) {
+            if (--cyw43_sleep == 0) {
+                pendsv_schedule_dispatch(PENDSV_DISPATCH_CYW43, cyw43_poll);
+            }
+        }
+    }
+    #endif
 }
 
 #endif // MICROPY_PY_LWIP
diff --git a/ports/mimxrt/mpnimbleport.c b/ports/mimxrt/mpnimbleport.c
new file mode 100644
index 0000000000..e2d39e271c
--- /dev/null
+++ b/ports/mimxrt/mpnimbleport.c
@@ -0,0 +1,78 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2019 Jim Mussared
+ * Copyright (c) 2020 Damien P. George
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include "py/runtime.h"
+#include "py/mperrno.h"
+#include "py/mphal.h"
+
+#if MICROPY_PY_BLUETOOTH && MICROPY_BLUETOOTH_NIMBLE
+
+#define DEBUG_printf(...) // printf("mpnimbleport.c: " __VA_ARGS__)
+
+#include "host/ble_hs.h"
+#include "nimble/nimble_npl.h"
+
+#include "extmod/mpbthci.h"
+#include "extmod/modbluetooth.h"
+#include "extmod/nimble/modbluetooth_nimble.h"
+#include "extmod/nimble/hal/hal_uart.h"
+#include "mpbthciport.h"
+
+// Get any pending data from the UART and send it to NimBLE's HCI buffers.
+// Any further processing by NimBLE will be run via its event queue.
+void mp_bluetooth_hci_poll(void) {
+    if (mp_bluetooth_nimble_ble_state >= MP_BLUETOOTH_NIMBLE_BLE_STATE_WAITING_FOR_SYNC) {
+        // DEBUG_printf("mp_bluetooth_hci_poll_uart %d\n", mp_bluetooth_nimble_ble_state);
+
+        // Run any timers.
+        mp_bluetooth_nimble_os_callout_process();
+
+        // Process incoming UART data, and run events as they are generated.
+        mp_bluetooth_nimble_hci_uart_process(true);
+
+        // Run any remaining events (e.g. if there was no UART data).
+        mp_bluetooth_nimble_os_eventq_run_all();
+    }
+
+    if (mp_bluetooth_nimble_ble_state != MP_BLUETOOTH_NIMBLE_BLE_STATE_OFF) {
+        // Call this function again in 128ms to check for new events.
+        // TODO: improve this by only calling back when needed.
+        mp_bluetooth_hci_poll_in_ms(128);
+    }
+}
+
+// --- Port-specific helpers for the generic NimBLE bindings. -----------------
+
+void mp_bluetooth_nimble_hci_uart_wfi(void) {
+    __WFI();
+
+    // This is called while NimBLE is waiting in ble_npl_sem_pend, i.e. waiting for an HCI ACK.
+    // Do not need to run events here (it must not invoke Python code), only processing incoming HCI data.
+    mp_bluetooth_nimble_hci_uart_process(false);
+}
+
+#endif // MICROPY_PY_BLUETOOTH && MICROPY_BLUETOOTH_NIMBLE
diff --git a/ports/mimxrt/mpnimbleport.h b/ports/mimxrt/mpnimbleport.h
new file mode 100644
index 0000000000..78f4fc9b00
--- /dev/null
+++ b/ports/mimxrt/mpnimbleport.h
@@ -0,0 +1,30 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2020 Jim Mussared
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#ifndef MICROPY_INCLUDED_MIMXRT_NIMBLE_PORT_H
+#define MICROPY_INCLUDED_MIMXRT_NIMBLE_PORT_H
+
+#endif // MICROPY_INCLUDED_MIMXRT_NIMBLE_PORT_H
diff --git a/ports/mimxrt/pendsv.c b/ports/mimxrt/pendsv.c
index 11f2ef5e1c..46d13a5aca 100644
--- a/ports/mimxrt/pendsv.c
+++ b/ports/mimxrt/pendsv.c
@@ -28,9 +28,7 @@
 
 #include "py/runtime.h"
 #include "pendsv.h"
-
-#define NVIC_PRIORITYGROUP_4    ((uint32_t)0x00000003)
-#define IRQ_PRI_PENDSV          NVIC_EncodePriority(NVIC_PRIORITYGROUP_4, 15, 0)
+#include "irq.h"
 
 #if defined(PENDSV_DISPATCH_NUM_SLOTS)
 pendsv_dispatch_t pendsv_dispatch_table[PENDSV_DISPATCH_NUM_SLOTS];
diff --git a/ports/mimxrt/pendsv.h b/ports/mimxrt/pendsv.h
index e68f487fb4..f3369b07fe 100644
--- a/ports/mimxrt/pendsv.h
+++ b/ports/mimxrt/pendsv.h
@@ -31,6 +31,9 @@ enum {
     #if MICROPY_PY_NETWORK && MICROPY_PY_LWIP
     PENDSV_DISPATCH_LWIP,
     #endif
+    #if MICROPY_PY_NETWORK_CYW43
+    PENDSV_DISPATCH_CYW43,
+    #endif
     MICROPY_BOARD_PENDSV_ENTRIES
     PENDSV_DISPATCH_MAX
 };
diff --git a/ports/mimxrt/pin.h b/ports/mimxrt/pin.h
index 63db55f8a7..aa86f05e82 100644
--- a/ports/mimxrt/pin.h
+++ b/ports/mimxrt/pin.h
@@ -39,6 +39,10 @@
     ((MODE) == PIN_MODE_OPEN_DRAIN) || \
     ((MODE) == PIN_MODE_ALT))
 
+#define IS_GPIO_IT_MODE(MODE) (((MODE) == PIN_MODE_IT_RISING) || \
+    ((MODE) == PIN_MODE_IT_FALLING) || \
+    ((MODE) == PIN_MODE_IT_BOTH))
+
 #define IS_GPIO_DRIVE(DRIVE) (((DRIVE) == PIN_DRIVE_OFF) || \
     ((DRIVE) == PIN_DRIVE_0) || \
     ((DRIVE) == PIN_DRIVE_1) || \
@@ -56,6 +60,9 @@ enum {
     PIN_MODE_OPEN_DRAIN,
     PIN_MODE_ALT,
     PIN_MODE_SKIP,
+    PIN_MODE_IT_RISING,
+    PIN_MODE_IT_FALLING,
+    PIN_MODE_IT_BOTH,
 };
 
 enum {
@@ -161,6 +168,8 @@ const machine_pin_af_obj_t *pin_find_af(const machine_pin_obj_t *pin, uint8_t fn
 const machine_pin_af_obj_t *pin_find_af_by_index(const machine_pin_obj_t *pin, mp_uint_t af_idx);
 const machine_pin_af_obj_t *pin_find_af_by_name(const machine_pin_obj_t *pin, const char *name);
 void machine_pin_set_mode(const machine_pin_obj_t *pin, uint8_t mode);
+void machine_pin_config(const machine_pin_obj_t *self, uint8_t mode,
+    uint8_t pull, uint8_t drive, uint8_t speed, uint8_t alt);
 uint32_t pin_generate_config(const uint32_t pull, const uint32_t mode, const uint32_t drive, uint32_t config_register);
 
 #endif // MICROPY_INCLUDED_MIMXRT_PIN_H
diff --git a/ports/mimxrt/sdio.c b/ports/mimxrt/sdio.c
new file mode 100644
index 0000000000..d97fef9e51
--- /dev/null
+++ b/ports/mimxrt/sdio.c
@@ -0,0 +1,334 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2023 Ibrahim Abdelkader <iabdalkader@openmv.io>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include <stdio.h>
+#include "py/mperrno.h"
+#include "py/mphal.h"
+#include "pin.h"
+#include "pendsv.h"
+
+#if MICROPY_PY_NETWORK_CYW43
+
+#include "fsl_usdhc.h"
+#include "fsl_iomuxc.h"
+
+#if MICROPY_HW_SDIO_SDMMC == 1
+#define SDMMC                       USDHC1
+#define SDMMC_IRQn                  USDHC1_IRQn
+#define SDMMC_CLOCK_DIV             kCLOCK_Usdhc1Div
+#define SDMMC_CLOCK_MUX             kCLOCK_Usdhc1Mux
+#ifndef MICROPY_HW_SDIO_CLK_ALT
+#define MICROPY_HW_SDIO_CMD_ALT     (0)
+#define MICROPY_HW_SDIO_CLK_ALT     (0)
+#define MICROPY_HW_SDIO_D0_ALT      (0)
+#define MICROPY_HW_SDIO_D1_ALT      (0)
+#define MICROPY_HW_SDIO_D2_ALT      (0)
+#define MICROPY_HW_SDIO_D3_ALT      (0)
+#endif
+#else
+#define SDMMC                       USDHC2
+#define SDMMC_IRQn                  USDHC2_IRQn
+#define SDMMC_CLOCK_DIV             kCLOCK_Usdhc2Div
+#define SDMMC_CLOCK_MUX             kCLOCK_Usdhc2Mux
+#ifndef MICROPY_HW_SDIO_CLK_ALT
+#define MICROPY_HW_SDIO_CMD_ALT     (6)
+#define MICROPY_HW_SDIO_CLK_ALT     (6)
+#define MICROPY_HW_SDIO_D0_ALT      (6)
+#define MICROPY_HW_SDIO_D1_ALT      (6)
+#define MICROPY_HW_SDIO_D2_ALT      (6)
+#define MICROPY_HW_SDIO_D3_ALT      (6)
+#endif
+#endif
+
+#define SDMMC_CLOCK_400KHZ      (400000U)
+#define SDMMC_CLOCK_25MHZ       (25000000U)
+#define SDMMC_CLOCK_50MHZ       (50000000U)
+
+#if SDIO_DEBUG
+#define debug_printf(...) mp_printf(&mp_plat_print, __VA_ARGS__)
+#else
+#define debug_printf(...)
+#endif
+
+#define DMA_DESCRIPTOR_BUFFER_SIZE (32U)
+AT_NONCACHEABLE_SECTION_ALIGN(
+    static uint32_t sdio_adma_descriptor_table[DMA_DESCRIPTOR_BUFFER_SIZE], USDHC_ADMA2_ADDRESS_ALIGN);
+
+typedef struct _mimxrt_sdmmc_t {
+    USDHC_Type *inst;
+    usdhc_handle_t handle;
+    volatile uint32_t xfer_flags;
+    volatile uint32_t xfer_error;
+} mimxrt_sdmmc_t;
+
+static mimxrt_sdmmc_t sdmmc = {
+    .inst = SDMMC,
+};
+
+typedef enum {
+    SDIO_TRANSFER_DATA_COMPLETE = (1 << 0),
+    SDIO_TRANSFER_CMD_COMPLETE  = (1 << 1),
+    SDIO_TRANSFER_ERROR         = (1 << 2),
+} sdio_xfer_flags_t;
+
+static uint32_t sdio_base_clk(void) {
+    return CLOCK_GetSysPfdFreq(kCLOCK_Pfd0) / (CLOCK_GetDiv(kCLOCK_Usdhc1Div) + 1U);
+}
+
+static uint32_t sdio_response_type(uint32_t cmd) {
+    switch (cmd) {
+        case 3:
+            return kCARD_ResponseTypeR6;
+        case 5:
+            return kCARD_ResponseTypeR4;
+        case 7:
+            return kCARD_ResponseTypeR1;
+        case 52:
+            return kCARD_ResponseTypeR5;
+        default:
+            return kCARD_ResponseTypeNone;
+    }
+}
+
+static void sdio_transfer_callback(USDHC_Type *base,
+    usdhc_handle_t *handle, status_t status, void *userData) {
+    if (status == kStatus_USDHC_TransferDataComplete) {
+        sdmmc.xfer_flags |= SDIO_TRANSFER_DATA_COMPLETE;
+    } else if (status == kStatus_USDHC_SendCommandSuccess) {
+        sdmmc.xfer_flags |= SDIO_TRANSFER_CMD_COMPLETE;
+    } else if (status != kStatus_USDHC_BusyTransferring) {
+        sdmmc.xfer_error = status;
+        sdmmc.xfer_flags |= SDIO_TRANSFER_ERROR;
+    }
+}
+
+static void sdio_interrupt_callback(USDHC_Type *base, void *userData) {
+    extern void (*cyw43_poll)(void);
+
+    USDHC_DisableInterruptSignal(base, kUSDHC_CardInterruptFlag);
+    USDHC_ClearInterruptStatusFlags(base, kUSDHC_CardInterruptFlag);
+
+    if (cyw43_poll) {
+        pendsv_schedule_dispatch(PENDSV_DISPATCH_CYW43, cyw43_poll);
+    }
+}
+
+void sdio_init(uint32_t irq_pri) {
+    machine_pin_config(MICROPY_HW_SDIO_CMD, PIN_MODE_ALT, PIN_PULL_UP_100K, PIN_DRIVE_6, 0, MICROPY_HW_SDIO_CMD_ALT);
+    machine_pin_config(MICROPY_HW_SDIO_CLK, PIN_MODE_ALT, PIN_PULL_DISABLED, PIN_DRIVE_6, 0, MICROPY_HW_SDIO_CLK_ALT);
+    machine_pin_config(MICROPY_HW_SDIO_D0, PIN_MODE_ALT, PIN_PULL_UP_100K, PIN_DRIVE_6, 0, MICROPY_HW_SDIO_D0_ALT);
+    machine_pin_config(MICROPY_HW_SDIO_D1, PIN_MODE_ALT, PIN_PULL_UP_100K, PIN_DRIVE_6, 0, MICROPY_HW_SDIO_D1_ALT);
+    machine_pin_config(MICROPY_HW_SDIO_D2, PIN_MODE_ALT, PIN_PULL_UP_100K, PIN_DRIVE_6, 0, MICROPY_HW_SDIO_D2_ALT);
+    machine_pin_config(MICROPY_HW_SDIO_D3, PIN_MODE_ALT, PIN_PULL_UP_100K, PIN_DRIVE_6, 0, MICROPY_HW_SDIO_D3_ALT);
+
+    // Configure PFD0 of PLL2 (system PLL) fractional divider to 24 resulting in:
+    //  with PFD0_clk = PLL2_clk * 18 / N
+    //       PFD0_clk = 528MHz   * 18 / 24 = 396MHz
+    CLOCK_InitSysPfd(kCLOCK_Pfd0, 24U);
+    CLOCK_SetDiv(SDMMC_CLOCK_DIV, 1U);  // USDHC_input_clk = PFD0_clk / 2
+    CLOCK_SetMux(SDMMC_CLOCK_MUX, 1U);  // Select PFD0 as clock input for USDHC
+
+    // Initialize USDHC
+    const usdhc_config_t config = {
+        .endianMode = kUSDHC_EndianModeLittle,
+        .dataTimeout = 0xFU,
+        .readBurstLen = 0,
+        .writeBurstLen = 0,
+        .readWatermarkLevel = 128U,
+        .writeWatermarkLevel = 128U,
+    };
+
+    USDHC_Init(sdmmc.inst, &config);
+    USDHC_Reset(SDMMC, kUSDHC_ResetAll, 1000U);
+    USDHC_DisableInterruptSignal(SDMMC, kUSDHC_AllInterruptFlags);
+    USDHC_SetSdClock(sdmmc.inst, sdio_base_clk(), SDMMC_CLOCK_25MHZ);
+    USDHC_SetDataBusWidth(sdmmc.inst, kUSDHC_DataBusWidth1Bit);
+
+    mp_hal_delay_ms(10);
+
+    NVIC_SetPriority(SDMMC_IRQn, irq_pri);
+    EnableIRQ(SDMMC_IRQn);
+
+    usdhc_transfer_callback_t callbacks = {
+        .SdioInterrupt = sdio_interrupt_callback,
+        .TransferComplete = sdio_transfer_callback,
+    };
+    USDHC_TransferCreateHandle(sdmmc.inst, &sdmmc.handle, &callbacks, NULL);
+}
+
+void sdio_deinit(void) {
+}
+
+void sdio_reenable(void) {
+}
+
+void sdio_enable_irq(bool enable) {
+    if (enable) {
+        USDHC_ClearInterruptStatusFlags(sdmmc.inst, kUSDHC_CardInterruptFlag);
+        USDHC_EnableInterruptStatus(sdmmc.inst, kUSDHC_CardInterruptFlag);
+        USDHC_EnableInterruptSignal(sdmmc.inst, kUSDHC_CardInterruptFlag);
+    } else {
+        USDHC_DisableInterruptStatus(sdmmc.inst, kUSDHC_CardInterruptFlag);
+        USDHC_ClearInterruptStatusFlags(sdmmc.inst, kUSDHC_CardInterruptFlag);
+        USDHC_DisableInterruptSignal(sdmmc.inst, kUSDHC_CardInterruptFlag);
+    }
+}
+
+void sdio_enable_high_speed_4bit(void) {
+    USDHC_SetSdClock(sdmmc.inst, sdio_base_clk(), SDMMC_CLOCK_50MHZ);
+    USDHC_SetDataBusWidth(sdmmc.inst, kUSDHC_DataBusWidth4Bit);
+}
+
+static status_t sdio_transfer_dma(USDHC_Type *base,
+    usdhc_handle_t *handle, usdhc_transfer_t *transfer, uint32_t timeout_ms) {
+    status_t status;
+    usdhc_adma_config_t dma_config = {
+        .dmaMode = kUSDHC_DmaModeAdma2,
+        #if !FSL_FEATURE_USDHC_HAS_NO_RW_BURST_LEN
+        .burstLen = kUSDHC_EnBurstLenForINCR,
+        #endif
+        .admaTable = sdio_adma_descriptor_table,
+        .admaTableWords = DMA_DESCRIPTOR_BUFFER_SIZE,
+    };
+
+    sdmmc.xfer_flags = 0;
+    sdmmc.xfer_error = 0;
+
+    uint32_t xfer_flags = SDIO_TRANSFER_CMD_COMPLETE;
+    if (transfer->data != NULL) {
+        xfer_flags |= SDIO_TRANSFER_DATA_COMPLETE;
+    }
+
+    status = USDHC_TransferNonBlocking(base, handle, &dma_config, transfer);
+    if (status != kStatus_Success) {
+        debug_printf("sdio_transfer_dma failed to start transfer error: %lu\n", status);
+        return status;
+    }
+
+    uint32_t start = mp_hal_ticks_ms();
+    while ((sdmmc.xfer_flags != xfer_flags) &&
+           !(sdmmc.xfer_flags & SDIO_TRANSFER_ERROR) &&
+           (mp_hal_ticks_ms() - start) < timeout_ms) {
+        MICROPY_EVENT_POLL_HOOK;
+    }
+
+    if (sdmmc.xfer_flags == 0) {
+        debug_printf("sdio_transfer_dma transfer timeout.\n");
+        return kStatus_Timeout;
+    } else if (sdmmc.xfer_flags != xfer_flags) {
+        debug_printf("sdio_transfer_dma transfer failed: %lu\n", sdmmc.xfer_error);
+        USDHC_Reset(base, kUSDHC_ResetCommand, 100);
+        if (xfer_flags & SDIO_TRANSFER_DATA_COMPLETE) {
+            USDHC_Reset(base, kUSDHC_ResetData, 100);
+        }
+        return sdmmc.xfer_error;
+    }
+
+    return kStatus_Success;
+}
+
+int sdio_transfer(uint32_t cmd, uint32_t arg, uint32_t *resp) {
+    status_t status;
+    usdhc_command_t command = {
+        .index = cmd,
+        .argument = arg,
+        .type = kCARD_CommandTypeNormal,
+        .responseType = sdio_response_type(cmd),
+        .responseErrorFlags = 0
+    };
+
+    usdhc_transfer_t transfer = {
+        .data = NULL,
+        .command = &command,
+    };
+
+    status = sdio_transfer_dma(sdmmc.inst, &sdmmc.handle, &transfer, 5000);
+
+    if (status != kStatus_Success) {
+        debug_printf("sdio_transfer failed!\n");
+        return -MP_EIO;
+    }
+
+    if (resp != NULL) {
+        *resp = command.response[0];
+    }
+
+    return 0;
+}
+
+int sdio_transfer_cmd53(bool write, uint32_t block_size, uint32_t arg, size_t len, uint8_t *buf) {
+    usdhc_data_t data = {
+        .enableAutoCommand12 = false,
+        .enableAutoCommand23 = false,
+        .enableIgnoreError = false,
+        .dataType = kUSDHC_TransferDataNormal,
+    };
+
+    usdhc_command_t command = {
+        .index = 53,
+        .argument = arg,
+        .type = kCARD_CommandTypeNormal,
+        .responseType = kCARD_ResponseTypeR5,
+        .responseErrorFlags = 0
+    };
+
+    usdhc_transfer_t transfer = {
+        .data = &data,
+        .command = &command,
+    };
+
+    if (write) {
+        data.rxData = NULL;
+        data.txData = (uint32_t *)buf;
+    } else {
+        data.txData = NULL;
+        data.rxData = (uint32_t *)buf;
+    }
+
+    if (arg & (1 << 27)) {
+        // SDIO_BLOCK_MODE
+        data.blockSize = block_size;
+        data.blockCount = len / block_size;
+    } else {
+        // SDIO_BYTE_MODE
+        data.blockSize = block_size;
+        data.blockCount = 1;
+    }
+
+    debug_printf("cmd53 rw: %d addr 0x%p blocksize %u blockcount %lu total %lu len %d\n",
+        write, buf, data.blockSize, data.blockCount, data.blockSize * data.blockCount, len);
+
+    status_t status = sdio_transfer_dma(sdmmc.inst, &sdmmc.handle, &transfer, 5000);
+
+    if (status != kStatus_Success) {
+        debug_printf("sdio_transfer_cmd53 failed!\n");
+        return -1;
+    }
+
+    return 0;
+}
+
+#endif
diff --git a/ports/mimxrt/sdio.h b/ports/mimxrt/sdio.h
new file mode 100644
index 0000000000..f8d6f498b6
--- /dev/null
+++ b/ports/mimxrt/sdio.h
@@ -0,0 +1,40 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2023 Ibrahim Abdelkader <iabdalkader@openmv.io>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+#ifndef MICROPY_INCLUDED_MIMXRT_SDIO_H
+#define MICROPY_INCLUDED_MIMXRT_SDIO_H
+
+#include <stdbool.h>
+#include <stdint.h>
+
+void sdio_init(uint32_t irq_pri);
+void sdio_deinit(void);
+void sdio_reenable(void);
+void sdio_enable_irq(bool enable);
+void sdio_enable_high_speed_4bit(void);
+int sdio_transfer(uint32_t cmd, uint32_t arg, uint32_t *resp);
+int sdio_transfer_cmd53(bool write, uint32_t block_size, uint32_t arg, size_t len, uint8_t *buf);
+
+#endif // MICROPY_INCLUDED_MIMXRT_SDIO_H
diff --git a/ports/nrf/Makefile b/ports/nrf/Makefile
index 3a4b0ef23d..5e9e31ad01 100644
--- a/ports/nrf/Makefile
+++ b/ports/nrf/Makefile
@@ -4,8 +4,8 @@ ifdef BOARD_DIR
 # the path as the board name.
 BOARD ?= $(notdir $(BOARD_DIR:/=))
 else
-# If not given on the command line, then default to pca10040.
-BOARD ?= pca10040
+# If not given on the command line, then default to PCA10040.
+BOARD ?= PCA10040
 BOARD_DIR ?= boards/$(BOARD)
 endif
 
diff --git a/ports/nrf/README.md b/ports/nrf/README.md
index fde04e61f1..889ead5d4d 100644
--- a/ports/nrf/README.md
+++ b/ports/nrf/README.md
@@ -41,7 +41,7 @@ This is a port of MicroPython to the Nordic Semiconductor nRF series of chips.
   * [PCA10056](http://www.nordicsemi.com/eng/Products/nRF52840-Preview-DK)
   * [PCA10059](https://www.nordicsemi.com/Software-and-Tools/Development-Kits/nRF52840-Dongle)
   * [Particle Xenon](https://docs.particle.io/xenon/)
-  * [nRF52840 MDK USB Dongle](boards/nrf52840-mdk-usb-dongle/README.md)
+  * [nRF52840 MDK USB Dongle](boards/NRF52840_MDK_USB_DONGLE/README.md)
 * nRF9160
   * [PCA10090](https://www.nordicsemi.com/Software-and-Tools/Development-Kits/nRF9160-DK)
   * [Actinius Icarus](https://www.actinius.com/icarus)
@@ -63,8 +63,8 @@ By default, the PCA10040 (nrf52832) is used as compile target. To build and flas
 Alternatively the target board could be defined:
 
     make submodules
-    make BOARD=pca10040
-    make BOARD=pca10040 deploy
+    make BOARD=PCA10040
+    make BOARD=PCA10040 deploy
 
 ## Compile without LTO enabled
 
@@ -73,7 +73,7 @@ targets in the nrf-port. The `-flto` linker flag can be toggled easily by using
 the argument LTO when building. The example below shows how to disable LTO for
 the compilation:
 
-    make BOARD=pca10040 LTO=0
+    make BOARD=PCA10040 LTO=0
 
 **Note**: There have been several issues with use of LTO in conjunction with
 GNU ARM Embedded Toolchain 7.2.1/4Q17. It's recommended to use a toolchain after
@@ -88,11 +88,11 @@ First prepare the bluetooth folder by downloading Bluetooth LE stacks and header
 
 If the Bluetooth stacks has been downloaded, compile the target with the following command:
 
-    make BOARD=pca10040 SD=s132
+    make BOARD=PCA10040 SD=s132
 
 The **make sd** will trigger a flash of the bluetooth stack before that application is flashed. Note that **make sd** will perform a full erase of the chip, which could cause 3rd party bootloaders to also be wiped.
 
-    make BOARD=pca10040 SD=s132 sd
+    make BOARD=PCA10040 SD=s132 sd
 
 Note: further tuning of features to include in bluetooth or even setting up the device to use REPL over Bluetooth can be configured in the `bluetooth_conf.h`.
 
@@ -104,7 +104,7 @@ it in the specific target board's `mpconfigboard.mk`.
 
 For example:
 
-    make BOARD=pca10040 FROZEN_MANIFEST=path/to/manifest.py
+    make BOARD=PCA10040 FROZEN_MANIFEST=path/to/manifest.py
 
 In case of using the target board's makefile, add a line similar to this:
 
@@ -117,7 +117,7 @@ As the `oofatfs` module is not having header guards that can exclude the impleme
 
 For example:
 
-     make BOARD=pca10040 MICROPY_VFS_FAT=1
+     make BOARD=PCA10040 MICROPY_VFS_FAT=1
 
 ## Enable MICROPY_VFS_LFS1 or MICROPY_VFS_LFS2
 
@@ -127,7 +127,7 @@ or `MICROPY_VFS_LFS2` can be set. This will be in addition of setting
 
 For example:
 
-    make BOARD=pca10056 MICROPY_VFS_LFS2=1
+    make BOARD=PCA10056 MICROPY_VFS_LFS2=1
 
 ## Set file system size
 
@@ -141,7 +141,7 @@ linker script syntax as it is passed directly.
 For example, if we want to override the default file system size set by the
 linker scripts to use 256K:
 
-    make BOARD=pca10056 MICROPY_VFS_LFS2=1 FS_SIZE=256K
+    make BOARD=PCA10056 MICROPY_VFS_LFS2=1 FS_SIZE=256K
 
 Also note that changing this size between builds might cause loss of files
 present from a previous firmware as it will format the file system due to a new
@@ -151,25 +151,25 @@ location.
 
 Target Board (BOARD) | Bluetooth Stack (SD)    | Bluetooth Support      | Bootloader     | Default Flash Util
 ---------------------|-------------------------|------------------------|----------------|-------------------
-microbit             | s110                    | Peripheral             |                | [PyOCD](#pyocdopenocd-targets)
-pca10000             | s110                    | Peripheral             |                | [Segger](#segger-targets)
-pca10001             | s110                    | Peripheral             |                | [Segger](#segger-targets)
-pca10028             | s110                    | Peripheral             |                | [Segger](#segger-targets)
-pca10031             | s110                    | Peripheral             |                | [Segger](#segger-targets)
-wt51822_s4at         | s110                    | Peripheral             |                | Manual, see [datasheet](https://4tronix.co.uk/picobot2/WT51822-S4AT.pdf) for pinout
-pca10040             | s132                    | Peripheral and Central |                | [Segger](#segger-targets)
-feather52            | s132                    | Peripheral and Central |                | Manual, SWDIO and SWCLK solder points on the bottom side of the board
-arduino_primo        | s132                    | Peripheral and Central |                | [PyOCD](#pyocdopenocd-targets)
-ibk_blyst_nano       | s132                    | Peripheral and Central |                | [IDAP](#idap-midap-link-targets)
-idk_blyst_nano       | s132                    | Peripheral and Central |                | [IDAP](#idap-midap-link-targets)
-blueio_tag_evim      | s132                    | Peripheral and Central |                | [IDAP](#idap-midap-link-targets)
-evk_nina_b1          | s132                    | Peripheral and Central |                | [Segger](#segger-targets)
-pca10056             | s140                    | Peripheral and Central |                | [Segger](#segger-targets)
-pca10059             | s140                    | Peripheral and Central | OpenBootloader | [nrfutil](#nrfutil-targets)
-particle_xenon       | s140                    | Peripheral and Central |                | [Black Magic Probe](#black-magic-probe-targets)
-nrf52840-mdk-usb-dongle | s140                 | Peripheral and Central | OpenBootloader | [nrfutil](#nrfutil-targets)
-pca10090             | None (bsdlib.a)         | None (LTE/GNSS)        |                | [Segger](#segger-targets)
-actinius_icarus      | None (bsdlib.a)         | None (LTE/GNSS)        |                | [Segger](#segger-targets)
+MICROBIT             | s110                    | Peripheral             |                | [PyOCD](#pyocdopenocd-targets)
+PCA10000             | s110                    | Peripheral             |                | [Segger](#segger-targets)
+PCA10001             | s110                    | Peripheral             |                | [Segger](#segger-targets)
+PCA10028             | s110                    | Peripheral             |                | [Segger](#segger-targets)
+PCA10031             | s110                    | Peripheral             |                | [Segger](#segger-targets)
+WT51822_S4AT         | s110                    | Peripheral             |                | Manual, see [datasheet](https://4tronix.co.uk/picobot2/WT51822-S4AT.pdf) for pinout
+PCA10040             | s132                    | Peripheral and Central |                | [Segger](#segger-targets)
+FEATHER52            | s132                    | Peripheral and Central |                | Manual, SWDIO and SWCLK solder points on the bottom side of the board
+ARDUINO_PRIMO        | s132                    | Peripheral and Central |                | [PyOCD](#pyocdopenocd-targets)
+IBK_BLYST_NANO       | s132                    | Peripheral and Central |                | [IDAP](#idap-midap-link-targets)
+IDK_BLYST_NANO       | s132                    | Peripheral and Central |                | [IDAP](#idap-midap-link-targets)
+BLUEIO_TAG_EVIM      | s132                    | Peripheral and Central |                | [IDAP](#idap-midap-link-targets)
+EVK_NINA_B1          | s132                    | Peripheral and Central |                | [Segger](#segger-targets)
+PCA10056             | s140                    | Peripheral and Central |                | [Segger](#segger-targets)
+PCA10059             | s140                    | Peripheral and Central | OpenBootloader | [nrfutil](#nrfutil-targets)
+PARTICLE_XENON       | s140                    | Peripheral and Central |                | [Black Magic Probe](#black-magic-probe-targets)
+NRF52840_MDK_USB_DONGLE | s140                 | Peripheral and Central | OpenBootloader | [nrfutil](#nrfutil-targets)
+PCA10090             | None (bsdlib.a)         | None (LTE/GNSS)        |                | [Segger](#segger-targets)
+ACTINIUS_ICARUS      | None (bsdlib.a)         | None (LTE/GNSS)        |                | [Segger](#segger-targets)
 
 ## IDAP-M/IDAP-Link Targets
 
@@ -218,7 +218,7 @@ to trim of the MBR in case SoftDevice flashing is requested.
 `nrfutil` as flashing backend also requires a serial port parameter to be defined
 in addition to the `deploy` target of make. For example:
 
-    make BOARD=nrf52840-mdk-usb-dongle NRFUTIL_PORT=/dev/ttyACM0 deploy
+    make BOARD=NRF52840_MDK_USB_DONGLE NRFUTIL_PORT=/dev/ttyACM0 deploy
 
 If the target device is connected to `/dev/ttyACM0` serial port, the
 `NRFUTIL_PORT` parameter to make can be elided as it is the default serial
@@ -228,7 +228,7 @@ When enabling Bluetooth LE, as with the other flash utils, the SoftDevice
 needs to be flashed in the first firmware update. This can be done by issuing
 the `sd` target instead of `deploy`. For example:
 
-    make BOARD=nrf52840-mdk-usb-dongle SD=s140 NRFUTIL_PORT=/dev/ttyACM0 sd
+    make BOARD=NRF52840_MDK_USB_DONGLE SD=s140 NRFUTIL_PORT=/dev/ttyACM0 sd
 
 ## Bluetooth LE REPL
 
diff --git a/ports/nrf/boards/actinius_icarus/board.json b/ports/nrf/boards/ACTINIUS_ICARUS/board.json
similarity index 100%
rename from ports/nrf/boards/actinius_icarus/board.json
rename to ports/nrf/boards/ACTINIUS_ICARUS/board.json
diff --git a/ports/nrf/boards/actinius_icarus/mpconfigboard.h b/ports/nrf/boards/ACTINIUS_ICARUS/mpconfigboard.h
similarity index 100%
rename from ports/nrf/boards/actinius_icarus/mpconfigboard.h
rename to ports/nrf/boards/ACTINIUS_ICARUS/mpconfigboard.h
diff --git a/ports/nrf/boards/actinius_icarus/mpconfigboard.mk b/ports/nrf/boards/ACTINIUS_ICARUS/mpconfigboard.mk
similarity index 100%
rename from ports/nrf/boards/actinius_icarus/mpconfigboard.mk
rename to ports/nrf/boards/ACTINIUS_ICARUS/mpconfigboard.mk
diff --git a/ports/nrf/boards/actinius_icarus/pins.csv b/ports/nrf/boards/ACTINIUS_ICARUS/pins.csv
similarity index 100%
rename from ports/nrf/boards/actinius_icarus/pins.csv
rename to ports/nrf/boards/ACTINIUS_ICARUS/pins.csv
diff --git a/ports/nrf/boards/arduino_nano_33_ble_sense/board.c b/ports/nrf/boards/ARDUINO_NANO_33_BLE_SENSE/board.c
similarity index 100%
rename from ports/nrf/boards/arduino_nano_33_ble_sense/board.c
rename to ports/nrf/boards/ARDUINO_NANO_33_BLE_SENSE/board.c
diff --git a/ports/nrf/boards/arduino_nano_33_ble_sense/board.json b/ports/nrf/boards/ARDUINO_NANO_33_BLE_SENSE/board.json
similarity index 54%
rename from ports/nrf/boards/arduino_nano_33_ble_sense/board.json
rename to ports/nrf/boards/ARDUINO_NANO_33_BLE_SENSE/board.json
index 65a8e24350..9079fbd666 100644
--- a/ports/nrf/boards/arduino_nano_33_ble_sense/board.json
+++ b/ports/nrf/boards/ARDUINO_NANO_33_BLE_SENSE/board.json
@@ -4,15 +4,12 @@
     ],
     "docs": "",
     "features": [
-        "Bluetooth 5.0",
-        "IMU LSM9DS1",
-        "Humidity sensor HTS221",
-        "Pressure sensor LPS22H",
-        "Proximity, Light, RGB sensor APDS-9960",
-        "Microphone MPM3610",
-        "Crypto IC ARM CC310",
-        "USB-MICRO",
-        "Breadboard Friendly"
+        "BLE",
+        "Environment Sensor",
+        "IMU",
+        "Microphone",
+        "Secure Element",
+        "USB"
     ],
     "images": [
         "ABX00031_01.iso_998x749.jpg"
diff --git a/ports/nrf/boards/arduino_nano_33_ble_sense/deploy.md b/ports/nrf/boards/ARDUINO_NANO_33_BLE_SENSE/deploy.md
similarity index 100%
rename from ports/nrf/boards/arduino_nano_33_ble_sense/deploy.md
rename to ports/nrf/boards/ARDUINO_NANO_33_BLE_SENSE/deploy.md
diff --git a/ports/nrf/boards/arduino_nano_33_ble_sense/manifest.py b/ports/nrf/boards/ARDUINO_NANO_33_BLE_SENSE/manifest.py
similarity index 100%
rename from ports/nrf/boards/arduino_nano_33_ble_sense/manifest.py
rename to ports/nrf/boards/ARDUINO_NANO_33_BLE_SENSE/manifest.py
diff --git a/ports/nrf/boards/arduino_nano_33_ble_sense/modules/imu.py b/ports/nrf/boards/ARDUINO_NANO_33_BLE_SENSE/modules/imu.py
similarity index 100%
rename from ports/nrf/boards/arduino_nano_33_ble_sense/modules/imu.py
rename to ports/nrf/boards/ARDUINO_NANO_33_BLE_SENSE/modules/imu.py
diff --git a/ports/nrf/boards/arduino_nano_33_ble_sense/mpconfigboard.h b/ports/nrf/boards/ARDUINO_NANO_33_BLE_SENSE/mpconfigboard.h
similarity index 100%
rename from ports/nrf/boards/arduino_nano_33_ble_sense/mpconfigboard.h
rename to ports/nrf/boards/ARDUINO_NANO_33_BLE_SENSE/mpconfigboard.h
diff --git a/ports/nrf/boards/arduino_nano_33_ble_sense/mpconfigboard.mk b/ports/nrf/boards/ARDUINO_NANO_33_BLE_SENSE/mpconfigboard.mk
similarity index 77%
rename from ports/nrf/boards/arduino_nano_33_ble_sense/mpconfigboard.mk
rename to ports/nrf/boards/ARDUINO_NANO_33_BLE_SENSE/mpconfigboard.mk
index cb2ff5c6b8..148a9f1017 100644
--- a/ports/nrf/boards/arduino_nano_33_ble_sense/mpconfigboard.mk
+++ b/ports/nrf/boards/ARDUINO_NANO_33_BLE_SENSE/mpconfigboard.mk
@@ -4,7 +4,7 @@ MCU_SUB_VARIANT = nrf52840
 SOFTDEV_VERSION = 6.1.1
 SD=s140
 
-LD_FILES += boards/arduino_nano_33_ble_sense/nano_bootloader.ld boards/nrf52840_1M_256k.ld
+LD_FILES += boards/ARDUINO_NANO_33_BLE_SENSE/nano_bootloader.ld boards/nrf52840_1M_256k.ld
 
 NRF_DEFINES += -DNRF52840_XXAA
 
diff --git a/ports/nrf/boards/arduino_nano_33_ble_sense/nano_bootloader.ld b/ports/nrf/boards/ARDUINO_NANO_33_BLE_SENSE/nano_bootloader.ld
similarity index 100%
rename from ports/nrf/boards/arduino_nano_33_ble_sense/nano_bootloader.ld
rename to ports/nrf/boards/ARDUINO_NANO_33_BLE_SENSE/nano_bootloader.ld
diff --git a/ports/nrf/boards/arduino_nano_33_ble_sense/pins.csv b/ports/nrf/boards/ARDUINO_NANO_33_BLE_SENSE/pins.csv
similarity index 100%
rename from ports/nrf/boards/arduino_nano_33_ble_sense/pins.csv
rename to ports/nrf/boards/ARDUINO_NANO_33_BLE_SENSE/pins.csv
diff --git a/ports/nrf/boards/arduino_primo/board.json b/ports/nrf/boards/ARDUINO_PRIMO/board.json
similarity index 90%
rename from ports/nrf/boards/arduino_primo/board.json
rename to ports/nrf/boards/ARDUINO_PRIMO/board.json
index d16ce1c346..f7afed0ced 100644
--- a/ports/nrf/boards/arduino_primo/board.json
+++ b/ports/nrf/boards/ARDUINO_PRIMO/board.json
@@ -11,5 +11,5 @@
     "product": "arduino_primo",
     "thumbnail": "",
     "url": "",
-    "vendor": ""
+    "vendor": "Arduino"
 }
diff --git a/ports/nrf/boards/arduino_primo/mpconfigboard.h b/ports/nrf/boards/ARDUINO_PRIMO/mpconfigboard.h
similarity index 100%
rename from ports/nrf/boards/arduino_primo/mpconfigboard.h
rename to ports/nrf/boards/ARDUINO_PRIMO/mpconfigboard.h
diff --git a/ports/nrf/boards/arduino_primo/mpconfigboard.mk b/ports/nrf/boards/ARDUINO_PRIMO/mpconfigboard.mk
similarity index 100%
rename from ports/nrf/boards/arduino_primo/mpconfigboard.mk
rename to ports/nrf/boards/ARDUINO_PRIMO/mpconfigboard.mk
diff --git a/ports/nrf/boards/pca10040/pins.csv b/ports/nrf/boards/ARDUINO_PRIMO/pins.csv
similarity index 100%
rename from ports/nrf/boards/pca10040/pins.csv
rename to ports/nrf/boards/ARDUINO_PRIMO/pins.csv
diff --git a/ports/nrf/boards/blueio_tag_evim/board.json b/ports/nrf/boards/BLUEIO_TAG_EVIM/board.json
similarity index 100%
rename from ports/nrf/boards/blueio_tag_evim/board.json
rename to ports/nrf/boards/BLUEIO_TAG_EVIM/board.json
diff --git a/ports/nrf/boards/blueio_tag_evim/mpconfigboard.h b/ports/nrf/boards/BLUEIO_TAG_EVIM/mpconfigboard.h
similarity index 100%
rename from ports/nrf/boards/blueio_tag_evim/mpconfigboard.h
rename to ports/nrf/boards/BLUEIO_TAG_EVIM/mpconfigboard.h
diff --git a/ports/nrf/boards/idk_blyst_nano/mpconfigboard.mk b/ports/nrf/boards/BLUEIO_TAG_EVIM/mpconfigboard.mk
similarity index 100%
rename from ports/nrf/boards/idk_blyst_nano/mpconfigboard.mk
rename to ports/nrf/boards/BLUEIO_TAG_EVIM/mpconfigboard.mk
diff --git a/ports/nrf/boards/idk_blyst_nano/pins.csv b/ports/nrf/boards/BLUEIO_TAG_EVIM/pins.csv
similarity index 100%
rename from ports/nrf/boards/idk_blyst_nano/pins.csv
rename to ports/nrf/boards/BLUEIO_TAG_EVIM/pins.csv
diff --git a/ports/nrf/boards/dvk_bl652/board.json b/ports/nrf/boards/DVK_BL652/board.json
similarity index 100%
rename from ports/nrf/boards/dvk_bl652/board.json
rename to ports/nrf/boards/DVK_BL652/board.json
diff --git a/ports/nrf/boards/dvk_bl652/mpconfigboard.h b/ports/nrf/boards/DVK_BL652/mpconfigboard.h
similarity index 100%
rename from ports/nrf/boards/dvk_bl652/mpconfigboard.h
rename to ports/nrf/boards/DVK_BL652/mpconfigboard.h
diff --git a/ports/nrf/boards/dvk_bl652/mpconfigboard.mk b/ports/nrf/boards/DVK_BL652/mpconfigboard.mk
similarity index 100%
rename from ports/nrf/boards/dvk_bl652/mpconfigboard.mk
rename to ports/nrf/boards/DVK_BL652/mpconfigboard.mk
diff --git a/ports/nrf/boards/dvk_bl652/pins.csv b/ports/nrf/boards/DVK_BL652/pins.csv
similarity index 100%
rename from ports/nrf/boards/dvk_bl652/pins.csv
rename to ports/nrf/boards/DVK_BL652/pins.csv
diff --git a/ports/nrf/boards/evk_nina_b1/board.json b/ports/nrf/boards/EVK_NINA_B1/board.json
similarity index 100%
rename from ports/nrf/boards/evk_nina_b1/board.json
rename to ports/nrf/boards/EVK_NINA_B1/board.json
diff --git a/ports/nrf/boards/evk_nina_b1/mpconfigboard.h b/ports/nrf/boards/EVK_NINA_B1/mpconfigboard.h
similarity index 100%
rename from ports/nrf/boards/evk_nina_b1/mpconfigboard.h
rename to ports/nrf/boards/EVK_NINA_B1/mpconfigboard.h
diff --git a/ports/nrf/boards/pca10040/mpconfigboard.mk b/ports/nrf/boards/EVK_NINA_B1/mpconfigboard.mk
similarity index 100%
rename from ports/nrf/boards/pca10040/mpconfigboard.mk
rename to ports/nrf/boards/EVK_NINA_B1/mpconfigboard.mk
diff --git a/ports/nrf/boards/evk_nina_b1/pins.csv b/ports/nrf/boards/EVK_NINA_B1/pins.csv
similarity index 100%
rename from ports/nrf/boards/evk_nina_b1/pins.csv
rename to ports/nrf/boards/EVK_NINA_B1/pins.csv
diff --git a/ports/nrf/boards/evk_nina_b3/board.json b/ports/nrf/boards/EVK_NINA_B3/board.json
similarity index 100%
rename from ports/nrf/boards/evk_nina_b3/board.json
rename to ports/nrf/boards/EVK_NINA_B3/board.json
diff --git a/ports/nrf/boards/evk_nina_b3/mpconfigboard.h b/ports/nrf/boards/EVK_NINA_B3/mpconfigboard.h
similarity index 100%
rename from ports/nrf/boards/evk_nina_b3/mpconfigboard.h
rename to ports/nrf/boards/EVK_NINA_B3/mpconfigboard.h
diff --git a/ports/nrf/boards/evk_nina_b3/mpconfigboard.mk b/ports/nrf/boards/EVK_NINA_B3/mpconfigboard.mk
similarity index 100%
rename from ports/nrf/boards/evk_nina_b3/mpconfigboard.mk
rename to ports/nrf/boards/EVK_NINA_B3/mpconfigboard.mk
diff --git a/ports/nrf/boards/pca10056/pins.csv b/ports/nrf/boards/EVK_NINA_B3/pins.csv
similarity index 100%
rename from ports/nrf/boards/pca10056/pins.csv
rename to ports/nrf/boards/EVK_NINA_B3/pins.csv
diff --git a/ports/nrf/boards/feather52/board.json b/ports/nrf/boards/FEATHER52/board.json
similarity index 100%
rename from ports/nrf/boards/feather52/board.json
rename to ports/nrf/boards/FEATHER52/board.json
diff --git a/ports/nrf/boards/feather52/mpconfigboard.h b/ports/nrf/boards/FEATHER52/mpconfigboard.h
similarity index 100%
rename from ports/nrf/boards/feather52/mpconfigboard.h
rename to ports/nrf/boards/FEATHER52/mpconfigboard.h
diff --git a/ports/nrf/boards/feather52/mpconfigboard.mk b/ports/nrf/boards/FEATHER52/mpconfigboard.mk
similarity index 100%
rename from ports/nrf/boards/feather52/mpconfigboard.mk
rename to ports/nrf/boards/FEATHER52/mpconfigboard.mk
diff --git a/ports/nrf/boards/feather52/pins.csv b/ports/nrf/boards/FEATHER52/pins.csv
similarity index 100%
rename from ports/nrf/boards/feather52/pins.csv
rename to ports/nrf/boards/FEATHER52/pins.csv
diff --git a/ports/nrf/boards/ibk_blyst_nano/board.json b/ports/nrf/boards/IBK_BLYST_NANO/board.json
similarity index 100%
rename from ports/nrf/boards/ibk_blyst_nano/board.json
rename to ports/nrf/boards/IBK_BLYST_NANO/board.json
diff --git a/ports/nrf/boards/ibk_blyst_nano/mpconfigboard.h b/ports/nrf/boards/IBK_BLYST_NANO/mpconfigboard.h
similarity index 100%
rename from ports/nrf/boards/ibk_blyst_nano/mpconfigboard.h
rename to ports/nrf/boards/IBK_BLYST_NANO/mpconfigboard.h
diff --git a/ports/nrf/boards/ibk_blyst_nano/mpconfigboard.mk b/ports/nrf/boards/IBK_BLYST_NANO/mpconfigboard.mk
similarity index 100%
rename from ports/nrf/boards/ibk_blyst_nano/mpconfigboard.mk
rename to ports/nrf/boards/IBK_BLYST_NANO/mpconfigboard.mk
diff --git a/ports/nrf/boards/ibk_blyst_nano/pins.csv b/ports/nrf/boards/IBK_BLYST_NANO/pins.csv
similarity index 100%
rename from ports/nrf/boards/ibk_blyst_nano/pins.csv
rename to ports/nrf/boards/IBK_BLYST_NANO/pins.csv
diff --git a/ports/nrf/boards/idk_blyst_nano/board.json b/ports/nrf/boards/IDK_BLYST_NANO/board.json
similarity index 100%
rename from ports/nrf/boards/idk_blyst_nano/board.json
rename to ports/nrf/boards/IDK_BLYST_NANO/board.json
diff --git a/ports/nrf/boards/idk_blyst_nano/mpconfigboard.h b/ports/nrf/boards/IDK_BLYST_NANO/mpconfigboard.h
similarity index 100%
rename from ports/nrf/boards/idk_blyst_nano/mpconfigboard.h
rename to ports/nrf/boards/IDK_BLYST_NANO/mpconfigboard.h
diff --git a/ports/nrf/boards/blueio_tag_evim/mpconfigboard.mk b/ports/nrf/boards/IDK_BLYST_NANO/mpconfigboard.mk
similarity index 100%
rename from ports/nrf/boards/blueio_tag_evim/mpconfigboard.mk
rename to ports/nrf/boards/IDK_BLYST_NANO/mpconfigboard.mk
diff --git a/ports/nrf/boards/blueio_tag_evim/pins.csv b/ports/nrf/boards/IDK_BLYST_NANO/pins.csv
similarity index 100%
rename from ports/nrf/boards/blueio_tag_evim/pins.csv
rename to ports/nrf/boards/IDK_BLYST_NANO/pins.csv
diff --git a/ports/nrf/boards/microbit/board.json b/ports/nrf/boards/MICROBIT/board.json
similarity index 100%
rename from ports/nrf/boards/microbit/board.json
rename to ports/nrf/boards/MICROBIT/board.json
diff --git a/ports/nrf/boards/microbit/custom_nrf51822_s110_microbit.ld b/ports/nrf/boards/MICROBIT/custom_nrf51822_s110_microbit.ld
similarity index 100%
rename from ports/nrf/boards/microbit/custom_nrf51822_s110_microbit.ld
rename to ports/nrf/boards/MICROBIT/custom_nrf51822_s110_microbit.ld
diff --git a/ports/nrf/boards/microbit/modules/AUTHORS b/ports/nrf/boards/MICROBIT/modules/AUTHORS
similarity index 100%
rename from ports/nrf/boards/microbit/modules/AUTHORS
rename to ports/nrf/boards/MICROBIT/modules/AUTHORS
diff --git a/ports/nrf/boards/microbit/modules/LICENSE b/ports/nrf/boards/MICROBIT/modules/LICENSE
similarity index 100%
rename from ports/nrf/boards/microbit/modules/LICENSE
rename to ports/nrf/boards/MICROBIT/modules/LICENSE
diff --git a/ports/nrf/boards/microbit/modules/boardmodules.h b/ports/nrf/boards/MICROBIT/modules/boardmodules.h
similarity index 100%
rename from ports/nrf/boards/microbit/modules/boardmodules.h
rename to ports/nrf/boards/MICROBIT/modules/boardmodules.h
diff --git a/ports/nrf/boards/microbit/modules/boardmodules.mk b/ports/nrf/boards/MICROBIT/modules/boardmodules.mk
similarity index 91%
rename from ports/nrf/boards/microbit/modules/boardmodules.mk
rename to ports/nrf/boards/MICROBIT/modules/boardmodules.mk
index eb8f108615..84a606c448 100644
--- a/ports/nrf/boards/microbit/modules/boardmodules.mk
+++ b/ports/nrf/boards/MICROBIT/modules/boardmodules.mk
@@ -1,4 +1,4 @@
-BOARD_MICROBIT_DIR = boards/microbit/modules
+BOARD_MICROBIT_DIR = boards/MICROBIT/modules
 
 INC += -I./$(BOARD_MICROBIT_DIR)
 CFLAGS += -DBOARD_SPECIFIC_MODULES
diff --git a/ports/nrf/boards/microbit/modules/iters.c b/ports/nrf/boards/MICROBIT/modules/iters.c
similarity index 100%
rename from ports/nrf/boards/microbit/modules/iters.c
rename to ports/nrf/boards/MICROBIT/modules/iters.c
diff --git a/ports/nrf/boards/microbit/modules/iters.h b/ports/nrf/boards/MICROBIT/modules/iters.h
similarity index 100%
rename from ports/nrf/boards/microbit/modules/iters.h
rename to ports/nrf/boards/MICROBIT/modules/iters.h
diff --git a/ports/nrf/boards/microbit/modules/microbitconstimage.c b/ports/nrf/boards/MICROBIT/modules/microbitconstimage.c
similarity index 100%
rename from ports/nrf/boards/microbit/modules/microbitconstimage.c
rename to ports/nrf/boards/MICROBIT/modules/microbitconstimage.c
diff --git a/ports/nrf/boards/microbit/modules/microbitconstimage.h b/ports/nrf/boards/MICROBIT/modules/microbitconstimage.h
similarity index 100%
rename from ports/nrf/boards/microbit/modules/microbitconstimage.h
rename to ports/nrf/boards/MICROBIT/modules/microbitconstimage.h
diff --git a/ports/nrf/boards/microbit/modules/microbitconstimagetuples.c b/ports/nrf/boards/MICROBIT/modules/microbitconstimagetuples.c
similarity index 100%
rename from ports/nrf/boards/microbit/modules/microbitconstimagetuples.c
rename to ports/nrf/boards/MICROBIT/modules/microbitconstimagetuples.c
diff --git a/ports/nrf/boards/microbit/modules/microbitdisplay.c b/ports/nrf/boards/MICROBIT/modules/microbitdisplay.c
similarity index 100%
rename from ports/nrf/boards/microbit/modules/microbitdisplay.c
rename to ports/nrf/boards/MICROBIT/modules/microbitdisplay.c
diff --git a/ports/nrf/boards/microbit/modules/microbitdisplay.h b/ports/nrf/boards/MICROBIT/modules/microbitdisplay.h
similarity index 100%
rename from ports/nrf/boards/microbit/modules/microbitdisplay.h
rename to ports/nrf/boards/MICROBIT/modules/microbitdisplay.h
diff --git a/ports/nrf/boards/microbit/modules/microbitfont.h b/ports/nrf/boards/MICROBIT/modules/microbitfont.h
similarity index 100%
rename from ports/nrf/boards/microbit/modules/microbitfont.h
rename to ports/nrf/boards/MICROBIT/modules/microbitfont.h
diff --git a/ports/nrf/boards/microbit/modules/microbitimage.c b/ports/nrf/boards/MICROBIT/modules/microbitimage.c
similarity index 100%
rename from ports/nrf/boards/microbit/modules/microbitimage.c
rename to ports/nrf/boards/MICROBIT/modules/microbitimage.c
diff --git a/ports/nrf/boards/microbit/modules/microbitimage.h b/ports/nrf/boards/MICROBIT/modules/microbitimage.h
similarity index 100%
rename from ports/nrf/boards/microbit/modules/microbitimage.h
rename to ports/nrf/boards/MICROBIT/modules/microbitimage.h
diff --git a/ports/nrf/boards/microbit/modules/modmicrobit.c b/ports/nrf/boards/MICROBIT/modules/modmicrobit.c
similarity index 100%
rename from ports/nrf/boards/microbit/modules/modmicrobit.c
rename to ports/nrf/boards/MICROBIT/modules/modmicrobit.c
diff --git a/ports/nrf/boards/microbit/modules/modmicrobit.h b/ports/nrf/boards/MICROBIT/modules/modmicrobit.h
similarity index 100%
rename from ports/nrf/boards/microbit/modules/modmicrobit.h
rename to ports/nrf/boards/MICROBIT/modules/modmicrobit.h
diff --git a/ports/nrf/boards/microbit/mpconfigboard.h b/ports/nrf/boards/MICROBIT/mpconfigboard.h
similarity index 100%
rename from ports/nrf/boards/microbit/mpconfigboard.h
rename to ports/nrf/boards/MICROBIT/mpconfigboard.h
diff --git a/ports/nrf/boards/microbit/mpconfigboard.mk b/ports/nrf/boards/MICROBIT/mpconfigboard.mk
similarity index 79%
rename from ports/nrf/boards/microbit/mpconfigboard.mk
rename to ports/nrf/boards/MICROBIT/mpconfigboard.mk
index 6fdd2bc500..6c7e1b46b9 100644
--- a/ports/nrf/boards/microbit/mpconfigboard.mk
+++ b/ports/nrf/boards/MICROBIT/mpconfigboard.mk
@@ -4,7 +4,7 @@ MCU_SUB_VARIANT = nrf51822
 SOFTDEV_VERSION = 8.0.0
 
 ifneq ($(SD),)
-LD_FILES += boards/microbit/custom_nrf51822_s110_microbit.ld
+LD_FILES += boards/MICROBIT/custom_nrf51822_s110_microbit.ld
 FROZEN_MANIFEST ?=
 else
 MICROPY_VFS_LFS2 = 1
diff --git a/ports/nrf/boards/microbit/pins.csv b/ports/nrf/boards/MICROBIT/pins.csv
similarity index 100%
rename from ports/nrf/boards/microbit/pins.csv
rename to ports/nrf/boards/MICROBIT/pins.csv
diff --git a/ports/nrf/boards/nrf52840-mdk-usb-dongle/README.md b/ports/nrf/boards/NRF52840_MDK_USB_DONGLE/README.md
similarity index 100%
rename from ports/nrf/boards/nrf52840-mdk-usb-dongle/README.md
rename to ports/nrf/boards/NRF52840_MDK_USB_DONGLE/README.md
diff --git a/ports/nrf/boards/nrf52840-mdk-usb-dongle/board.json b/ports/nrf/boards/NRF52840_MDK_USB_DONGLE/board.json
similarity index 91%
rename from ports/nrf/boards/nrf52840-mdk-usb-dongle/board.json
rename to ports/nrf/boards/NRF52840_MDK_USB_DONGLE/board.json
index 853c375710..99d0caad23 100644
--- a/ports/nrf/boards/nrf52840-mdk-usb-dongle/board.json
+++ b/ports/nrf/boards/NRF52840_MDK_USB_DONGLE/board.json
@@ -11,5 +11,5 @@
     "product": "nrf52840-mdk-usb-dongle",
     "thumbnail": "",
     "url": "https://wiki.makerdiary.com/nrf52840-mdk-usb-dongle",
-    "vendor": ""
+    "vendor": "Makerdiary"
 }
diff --git a/ports/nrf/boards/nrf52840-mdk-usb-dongle/mpconfigboard.h b/ports/nrf/boards/NRF52840_MDK_USB_DONGLE/mpconfigboard.h
similarity index 100%
rename from ports/nrf/boards/nrf52840-mdk-usb-dongle/mpconfigboard.h
rename to ports/nrf/boards/NRF52840_MDK_USB_DONGLE/mpconfigboard.h
diff --git a/ports/nrf/boards/pca10059/mpconfigboard.mk b/ports/nrf/boards/NRF52840_MDK_USB_DONGLE/mpconfigboard.mk
similarity index 100%
rename from ports/nrf/boards/pca10059/mpconfigboard.mk
rename to ports/nrf/boards/NRF52840_MDK_USB_DONGLE/mpconfigboard.mk
diff --git a/ports/nrf/boards/nrf52840-mdk-usb-dongle/pins.csv b/ports/nrf/boards/NRF52840_MDK_USB_DONGLE/pins.csv
similarity index 100%
rename from ports/nrf/boards/nrf52840-mdk-usb-dongle/pins.csv
rename to ports/nrf/boards/NRF52840_MDK_USB_DONGLE/pins.csv
diff --git a/ports/nrf/boards/particle_xenon/board.json b/ports/nrf/boards/PARTICLE_XENON/board.json
similarity index 100%
rename from ports/nrf/boards/particle_xenon/board.json
rename to ports/nrf/boards/PARTICLE_XENON/board.json
diff --git a/ports/nrf/boards/particle_xenon/mpconfigboard.h b/ports/nrf/boards/PARTICLE_XENON/mpconfigboard.h
similarity index 100%
rename from ports/nrf/boards/particle_xenon/mpconfigboard.h
rename to ports/nrf/boards/PARTICLE_XENON/mpconfigboard.h
diff --git a/ports/nrf/boards/particle_xenon/mpconfigboard.mk b/ports/nrf/boards/PARTICLE_XENON/mpconfigboard.mk
similarity index 100%
rename from ports/nrf/boards/particle_xenon/mpconfigboard.mk
rename to ports/nrf/boards/PARTICLE_XENON/mpconfigboard.mk
diff --git a/ports/nrf/boards/particle_xenon/pins.csv b/ports/nrf/boards/PARTICLE_XENON/pins.csv
similarity index 100%
rename from ports/nrf/boards/particle_xenon/pins.csv
rename to ports/nrf/boards/PARTICLE_XENON/pins.csv
diff --git a/ports/nrf/boards/pca10000/board.json b/ports/nrf/boards/PCA10000/board.json
similarity index 100%
rename from ports/nrf/boards/pca10000/board.json
rename to ports/nrf/boards/PCA10000/board.json
diff --git a/ports/nrf/boards/pca10000/mpconfigboard.h b/ports/nrf/boards/PCA10000/mpconfigboard.h
similarity index 100%
rename from ports/nrf/boards/pca10000/mpconfigboard.h
rename to ports/nrf/boards/PCA10000/mpconfigboard.h
diff --git a/ports/nrf/boards/pca10001/mpconfigboard.mk b/ports/nrf/boards/PCA10000/mpconfigboard.mk
similarity index 100%
rename from ports/nrf/boards/pca10001/mpconfigboard.mk
rename to ports/nrf/boards/PCA10000/mpconfigboard.mk
diff --git a/ports/nrf/boards/pca10000/pins.csv b/ports/nrf/boards/PCA10000/pins.csv
similarity index 100%
rename from ports/nrf/boards/pca10000/pins.csv
rename to ports/nrf/boards/PCA10000/pins.csv
diff --git a/ports/nrf/boards/pca10001/board.json b/ports/nrf/boards/PCA10001/board.json
similarity index 100%
rename from ports/nrf/boards/pca10001/board.json
rename to ports/nrf/boards/PCA10001/board.json
diff --git a/ports/nrf/boards/pca10001/mpconfigboard.h b/ports/nrf/boards/PCA10001/mpconfigboard.h
similarity index 100%
rename from ports/nrf/boards/pca10001/mpconfigboard.h
rename to ports/nrf/boards/PCA10001/mpconfigboard.h
diff --git a/ports/nrf/boards/pca10000/mpconfigboard.mk b/ports/nrf/boards/PCA10001/mpconfigboard.mk
similarity index 100%
rename from ports/nrf/boards/pca10000/mpconfigboard.mk
rename to ports/nrf/boards/PCA10001/mpconfigboard.mk
diff --git a/ports/nrf/boards/pca10001/pins.csv b/ports/nrf/boards/PCA10001/pins.csv
similarity index 100%
rename from ports/nrf/boards/pca10001/pins.csv
rename to ports/nrf/boards/PCA10001/pins.csv
diff --git a/ports/nrf/boards/pca10028/board.json b/ports/nrf/boards/PCA10028/board.json
similarity index 100%
rename from ports/nrf/boards/pca10028/board.json
rename to ports/nrf/boards/PCA10028/board.json
diff --git a/ports/nrf/boards/pca10028/mpconfigboard.h b/ports/nrf/boards/PCA10028/mpconfigboard.h
similarity index 100%
rename from ports/nrf/boards/pca10028/mpconfigboard.h
rename to ports/nrf/boards/PCA10028/mpconfigboard.h
diff --git a/ports/nrf/boards/pca10031/mpconfigboard.mk b/ports/nrf/boards/PCA10028/mpconfigboard.mk
similarity index 100%
rename from ports/nrf/boards/pca10031/mpconfigboard.mk
rename to ports/nrf/boards/PCA10028/mpconfigboard.mk
diff --git a/ports/nrf/boards/pca10028/pins.csv b/ports/nrf/boards/PCA10028/pins.csv
similarity index 100%
rename from ports/nrf/boards/pca10028/pins.csv
rename to ports/nrf/boards/PCA10028/pins.csv
diff --git a/ports/nrf/boards/pca10031/board.json b/ports/nrf/boards/PCA10031/board.json
similarity index 100%
rename from ports/nrf/boards/pca10031/board.json
rename to ports/nrf/boards/PCA10031/board.json
diff --git a/ports/nrf/boards/pca10031/mpconfigboard.h b/ports/nrf/boards/PCA10031/mpconfigboard.h
similarity index 100%
rename from ports/nrf/boards/pca10031/mpconfigboard.h
rename to ports/nrf/boards/PCA10031/mpconfigboard.h
diff --git a/ports/nrf/boards/pca10028/mpconfigboard.mk b/ports/nrf/boards/PCA10031/mpconfigboard.mk
similarity index 100%
rename from ports/nrf/boards/pca10028/mpconfigboard.mk
rename to ports/nrf/boards/PCA10031/mpconfigboard.mk
diff --git a/ports/nrf/boards/pca10031/pins.csv b/ports/nrf/boards/PCA10031/pins.csv
similarity index 100%
rename from ports/nrf/boards/pca10031/pins.csv
rename to ports/nrf/boards/PCA10031/pins.csv
diff --git a/ports/nrf/boards/pca10040/board.json b/ports/nrf/boards/PCA10040/board.json
similarity index 100%
rename from ports/nrf/boards/pca10040/board.json
rename to ports/nrf/boards/PCA10040/board.json
diff --git a/ports/nrf/boards/pca10040/mpconfigboard.h b/ports/nrf/boards/PCA10040/mpconfigboard.h
similarity index 100%
rename from ports/nrf/boards/pca10040/mpconfigboard.h
rename to ports/nrf/boards/PCA10040/mpconfigboard.h
diff --git a/ports/nrf/boards/evk_nina_b1/mpconfigboard.mk b/ports/nrf/boards/PCA10040/mpconfigboard.mk
similarity index 100%
rename from ports/nrf/boards/evk_nina_b1/mpconfigboard.mk
rename to ports/nrf/boards/PCA10040/mpconfigboard.mk
diff --git a/ports/nrf/boards/arduino_primo/pins.csv b/ports/nrf/boards/PCA10040/pins.csv
similarity index 100%
rename from ports/nrf/boards/arduino_primo/pins.csv
rename to ports/nrf/boards/PCA10040/pins.csv
diff --git a/ports/nrf/boards/pca10056/board.json b/ports/nrf/boards/PCA10056/board.json
similarity index 100%
rename from ports/nrf/boards/pca10056/board.json
rename to ports/nrf/boards/PCA10056/board.json
diff --git a/ports/nrf/boards/pca10056/mpconfigboard.h b/ports/nrf/boards/PCA10056/mpconfigboard.h
similarity index 100%
rename from ports/nrf/boards/pca10056/mpconfigboard.h
rename to ports/nrf/boards/PCA10056/mpconfigboard.h
diff --git a/ports/nrf/boards/pca10056/mpconfigboard.mk b/ports/nrf/boards/PCA10056/mpconfigboard.mk
similarity index 100%
rename from ports/nrf/boards/pca10056/mpconfigboard.mk
rename to ports/nrf/boards/PCA10056/mpconfigboard.mk
diff --git a/ports/nrf/boards/evk_nina_b3/pins.csv b/ports/nrf/boards/PCA10056/pins.csv
similarity index 100%
rename from ports/nrf/boards/evk_nina_b3/pins.csv
rename to ports/nrf/boards/PCA10056/pins.csv
diff --git a/ports/nrf/boards/pca10059/board.json b/ports/nrf/boards/PCA10059/board.json
similarity index 100%
rename from ports/nrf/boards/pca10059/board.json
rename to ports/nrf/boards/PCA10059/board.json
diff --git a/ports/nrf/boards/pca10059/modules/boardmodules.h b/ports/nrf/boards/PCA10059/modules/boardmodules.h
similarity index 100%
rename from ports/nrf/boards/pca10059/modules/boardmodules.h
rename to ports/nrf/boards/PCA10059/modules/boardmodules.h
diff --git a/ports/nrf/boards/pca10059/modules/boardmodules.mk b/ports/nrf/boards/PCA10059/modules/boardmodules.mk
similarity index 85%
rename from ports/nrf/boards/pca10059/modules/boardmodules.mk
rename to ports/nrf/boards/PCA10059/modules/boardmodules.mk
index 413790fbea..d1457cde7c 100644
--- a/ports/nrf/boards/pca10059/modules/boardmodules.mk
+++ b/ports/nrf/boards/PCA10059/modules/boardmodules.mk
@@ -1,4 +1,4 @@
-BOARD_PCA10059_DIR = boards/pca10059/modules
+BOARD_PCA10059_DIR = boards/PCA10059/modules
 
 INC += -I./$(BOARD_PCA10059_DIR)
 CFLAGS += -DBOARD_SPECIFIC_MODULES
diff --git a/ports/nrf/boards/pca10059/modules/recover_uicr_regout0.c b/ports/nrf/boards/PCA10059/modules/recover_uicr_regout0.c
similarity index 100%
rename from ports/nrf/boards/pca10059/modules/recover_uicr_regout0.c
rename to ports/nrf/boards/PCA10059/modules/recover_uicr_regout0.c
diff --git a/ports/nrf/boards/pca10059/mpconfigboard.h b/ports/nrf/boards/PCA10059/mpconfigboard.h
similarity index 100%
rename from ports/nrf/boards/pca10059/mpconfigboard.h
rename to ports/nrf/boards/PCA10059/mpconfigboard.h
diff --git a/ports/nrf/boards/nrf52840-mdk-usb-dongle/mpconfigboard.mk b/ports/nrf/boards/PCA10059/mpconfigboard.mk
similarity index 100%
rename from ports/nrf/boards/nrf52840-mdk-usb-dongle/mpconfigboard.mk
rename to ports/nrf/boards/PCA10059/mpconfigboard.mk
diff --git a/ports/nrf/boards/pca10059/pins.csv b/ports/nrf/boards/PCA10059/pins.csv
similarity index 100%
rename from ports/nrf/boards/pca10059/pins.csv
rename to ports/nrf/boards/PCA10059/pins.csv
diff --git a/ports/nrf/boards/pca10090/board.json b/ports/nrf/boards/PCA10090/board.json
similarity index 100%
rename from ports/nrf/boards/pca10090/board.json
rename to ports/nrf/boards/PCA10090/board.json
diff --git a/ports/nrf/boards/pca10090/mpconfigboard.h b/ports/nrf/boards/PCA10090/mpconfigboard.h
similarity index 100%
rename from ports/nrf/boards/pca10090/mpconfigboard.h
rename to ports/nrf/boards/PCA10090/mpconfigboard.h
diff --git a/ports/nrf/boards/pca10090/mpconfigboard.mk b/ports/nrf/boards/PCA10090/mpconfigboard.mk
similarity index 100%
rename from ports/nrf/boards/pca10090/mpconfigboard.mk
rename to ports/nrf/boards/PCA10090/mpconfigboard.mk
diff --git a/ports/nrf/boards/pca10090/pins.csv b/ports/nrf/boards/PCA10090/pins.csv
similarity index 100%
rename from ports/nrf/boards/pca10090/pins.csv
rename to ports/nrf/boards/PCA10090/pins.csv
diff --git a/ports/nrf/boards/seeed_xiao_nrf52/XIAO_bootloader.ld b/ports/nrf/boards/SEEED_XIAO_NRF52/XIAO_bootloader.ld
similarity index 100%
rename from ports/nrf/boards/seeed_xiao_nrf52/XIAO_bootloader.ld
rename to ports/nrf/boards/SEEED_XIAO_NRF52/XIAO_bootloader.ld
diff --git a/ports/nrf/boards/seeed_xiao_nrf52/board.c b/ports/nrf/boards/SEEED_XIAO_NRF52/board.c
similarity index 100%
rename from ports/nrf/boards/seeed_xiao_nrf52/board.c
rename to ports/nrf/boards/SEEED_XIAO_NRF52/board.c
diff --git a/ports/nrf/boards/seeed_xiao_nrf52/board.json b/ports/nrf/boards/SEEED_XIAO_NRF52/board.json
similarity index 62%
rename from ports/nrf/boards/seeed_xiao_nrf52/board.json
rename to ports/nrf/boards/SEEED_XIAO_NRF52/board.json
index 619a7c23b9..d40355bb2e 100644
--- a/ports/nrf/boards/seeed_xiao_nrf52/board.json
+++ b/ports/nrf/boards/SEEED_XIAO_NRF52/board.json
@@ -4,14 +4,13 @@
     ],
     "docs": "",
     "features": [
-        "Bluetooth 5.0",
-        "IMU LSM6DS3TR",
-        "Microphone MSM261D3526H1CPM",
-        "USB-C",
-        "Breadboard Friendly",
-        "Battery Management",
+        "BLE",
+        "Battery Charging",
+        "External Flash",
+        "IMU",
+        "Microphone",
         "RGB LED",
-        "QSPI Flash"
+        "USB-C"
     ],
     "images": [
         "XIAO_nrf52840_front.jpg"
diff --git a/ports/nrf/boards/seeed_xiao_nrf52/deploy.md b/ports/nrf/boards/SEEED_XIAO_NRF52/deploy.md
similarity index 100%
rename from ports/nrf/boards/seeed_xiao_nrf52/deploy.md
rename to ports/nrf/boards/SEEED_XIAO_NRF52/deploy.md
diff --git a/ports/nrf/boards/seeed_xiao_nrf52/mpconfigboard.h b/ports/nrf/boards/SEEED_XIAO_NRF52/mpconfigboard.h
similarity index 100%
rename from ports/nrf/boards/seeed_xiao_nrf52/mpconfigboard.h
rename to ports/nrf/boards/SEEED_XIAO_NRF52/mpconfigboard.h
diff --git a/ports/nrf/boards/seeed_xiao_nrf52/mpconfigboard.mk b/ports/nrf/boards/SEEED_XIAO_NRF52/mpconfigboard.mk
similarity index 82%
rename from ports/nrf/boards/seeed_xiao_nrf52/mpconfigboard.mk
rename to ports/nrf/boards/SEEED_XIAO_NRF52/mpconfigboard.mk
index c2fc219187..1f495a9c64 100644
--- a/ports/nrf/boards/seeed_xiao_nrf52/mpconfigboard.mk
+++ b/ports/nrf/boards/SEEED_XIAO_NRF52/mpconfigboard.mk
@@ -3,7 +3,7 @@ MCU_VARIANT = nrf52
 MCU_SUB_VARIANT = nrf52840
 SOFTDEV_VERSION = 7.3.0
 SD=s140
-LD_FILES += boards/seeed_xiao_nrf52/XIAO_bootloader.ld boards/nrf52840_1M_256k.ld
+LD_FILES += boards/SEEED_XIAO_NRF52/XIAO_bootloader.ld boards/nrf52840_1M_256k.ld
 
 NRF_DEFINES += -DNRF52840_XXAA
 
diff --git a/ports/nrf/boards/seeed_xiao_nrf52/pins.csv b/ports/nrf/boards/SEEED_XIAO_NRF52/pins.csv
similarity index 100%
rename from ports/nrf/boards/seeed_xiao_nrf52/pins.csv
rename to ports/nrf/boards/SEEED_XIAO_NRF52/pins.csv
diff --git a/ports/nrf/boards/wt51822_s4at/board.json b/ports/nrf/boards/WT51822_S4AT/board.json
similarity index 100%
rename from ports/nrf/boards/wt51822_s4at/board.json
rename to ports/nrf/boards/WT51822_S4AT/board.json
diff --git a/ports/nrf/boards/wt51822_s4at/mpconfigboard.h b/ports/nrf/boards/WT51822_S4AT/mpconfigboard.h
similarity index 100%
rename from ports/nrf/boards/wt51822_s4at/mpconfigboard.h
rename to ports/nrf/boards/WT51822_S4AT/mpconfigboard.h
diff --git a/ports/nrf/boards/wt51822_s4at/mpconfigboard.mk b/ports/nrf/boards/WT51822_S4AT/mpconfigboard.mk
similarity index 100%
rename from ports/nrf/boards/wt51822_s4at/mpconfigboard.mk
rename to ports/nrf/boards/WT51822_S4AT/mpconfigboard.mk
diff --git a/ports/nrf/boards/wt51822_s4at/pins.csv b/ports/nrf/boards/WT51822_S4AT/pins.csv
similarity index 100%
rename from ports/nrf/boards/wt51822_s4at/pins.csv
rename to ports/nrf/boards/WT51822_S4AT/pins.csv
diff --git a/ports/nrf/examples/ssd1306_mod.py b/ports/nrf/examples/ssd1306_mod.py
index b083a3aa7e..d42d165fa8 100644
--- a/ports/nrf/examples/ssd1306_mod.py
+++ b/ports/nrf/examples/ssd1306_mod.py
@@ -19,6 +19,7 @@
 # disp = SSD1306_I2C_Mod(128, 64, i2c)
 
 from ssd1306 import SSD1306_I2C
+from micropython import const
 
 SET_COL_ADDR = const(0x21)
 SET_PAGE_ADDR = const(0x22)
diff --git a/ports/nrf/examples/ubluepy_eddystone.py b/ports/nrf/examples/ubluepy_eddystone.py
index 96818d01c2..c98a2266f5 100644
--- a/ports/nrf/examples/ubluepy_eddystone.py
+++ b/ports/nrf/examples/ubluepy_eddystone.py
@@ -1,3 +1,4 @@
+from micropython import const
 from ubluepy import Peripheral, constants
 
 BLE_GAP_ADV_FLAG_LE_GENERAL_DISC_MODE = const(0x02)
diff --git a/ports/qemu-arm/test-frzmpy/frozen_asm.py b/ports/qemu-arm/test-frzmpy/frozen_asm.py
index 2c7f5c92cd..ba43264b38 100644
--- a/ports/qemu-arm/test-frzmpy/frozen_asm.py
+++ b/ports/qemu-arm/test-frzmpy/frozen_asm.py
@@ -1,5 +1,7 @@
 # Test freezing inline-asm code.
 
+# ruff: noqa: F821 - @asm_thumb decorator adds names to function scope
+
 import micropython
 
 
diff --git a/ports/renesas-ra/boards/EK_RA4M1/board.json b/ports/renesas-ra/boards/EK_RA4M1/board.json
index bab3bcacee..4d8dcd5e6d 100644
--- a/ports/renesas-ra/boards/EK_RA4M1/board.json
+++ b/ports/renesas-ra/boards/EK_RA4M1/board.json
@@ -3,17 +3,11 @@
         "../deploy.md"
     ],
     "docs": "",
-    "features": [
-	"UART",
-	"SPI",
-	"I2C",
-	"ADC"
-    ],
-    "id": "EK-RA4M1",
+    "features": [],
     "images": [
         "ek_ra4m1_board.jpg"
     ],
-    "mcu": "RA4M1",
+    "mcu": "ra4m1",
     "product": "EK-RA4M1",
     "thumbnail": "",
     "url": "https://www.renesas.com/products/microcontrollers-microprocessors/ra-cortex-m-mcus/ek-ra4m1-evaluation-kit-ra4m1-mcu-group",
diff --git a/ports/renesas-ra/boards/EK_RA4W1/board.json b/ports/renesas-ra/boards/EK_RA4W1/board.json
index db06b6751d..edc4fcbfe0 100644
--- a/ports/renesas-ra/boards/EK_RA4W1/board.json
+++ b/ports/renesas-ra/boards/EK_RA4W1/board.json
@@ -3,17 +3,11 @@
         "../deploy.md"
     ],
     "docs": "",
-    "features": [
-	"UART",
-	"SPI",
-	"I2C",
-	"ADC"
-    ],
-    "id": "EK-RA4W1",
+    "features": [],
     "images": [
         "ek_ra4w1_board.jpg"
     ],
-    "mcu": "RA4W1",
+    "mcu": "ra4w1",
     "product": "EK-RA4W1",
     "thumbnail": "",
     "url": "https://www.renesas.com/products/microcontrollers-microprocessors/ra-cortex-m-mcus/ek-ra4w1-evaluation-kit-ra4w1-mcu-group",
diff --git a/ports/renesas-ra/boards/EK_RA6M1/board.json b/ports/renesas-ra/boards/EK_RA6M1/board.json
index babcc5c166..3bdb08b92f 100644
--- a/ports/renesas-ra/boards/EK_RA6M1/board.json
+++ b/ports/renesas-ra/boards/EK_RA6M1/board.json
@@ -3,17 +3,11 @@
         "../deploy.md"
     ],
     "docs": "",
-    "features": [
-	"UART",
-	"SPI",
-	"I2C",
-	"ADC"
-    ],
-    "id": "EK-RA6M1",
+    "features": [],
     "images": [
         "ek_ra6m1_board.jpg"
     ],
-    "mcu": "RA6M1",
+    "mcu": "ra6m1",
     "product": "EK-RA6M1",
     "thumbnail": "",
     "url": "https://www.renesas.com/products/microcontrollers-microprocessors/ra-cortex-m-mcus/ek-ra6m1-evaluation-kit-ra6m1-mcu-group",
diff --git a/ports/renesas-ra/boards/EK_RA6M2/board.json b/ports/renesas-ra/boards/EK_RA6M2/board.json
index 63547d8807..5760b19736 100644
--- a/ports/renesas-ra/boards/EK_RA6M2/board.json
+++ b/ports/renesas-ra/boards/EK_RA6M2/board.json
@@ -3,13 +3,7 @@
         "../deploy.md"
     ],
     "docs": "",
-    "features": [
-	"UART",
-	"SPI",
-	"I2C",
-	"ADC"
-    ],
-    "id": "EK-RA6M2",
+    "features": [],
     "images": [
         "ek_ra6m2_board.jpg",
         "ek_ra6m2_j1_pins.jpg",
@@ -17,7 +11,7 @@
         "ek_ra6m2_j3_pins.jpg",
         "ek_ra6m2_j4_pins.jpg"
     ],
-    "mcu": "RA6M2",
+    "mcu": "ra6m2",
     "product": "EK-RA6M2",
     "thumbnail": "",
     "url": "https://www.renesas.com/products/microcontrollers-microprocessors/ra-cortex-m-mcus/ek-ra6m2-evaluation-kit-ra6m2-mcu-group",
diff --git a/ports/renesas-ra/boards/RA4M1_CLICKER/board.json b/ports/renesas-ra/boards/RA4M1_CLICKER/board.json
index 1c3c4c8e91..be1dd977c3 100644
--- a/ports/renesas-ra/boards/RA4M1_CLICKER/board.json
+++ b/ports/renesas-ra/boards/RA4M1_CLICKER/board.json
@@ -3,18 +3,12 @@
         "../deploy.md"
     ],
     "docs": "",
-    "features": [
-	"UART",
-	"SPI",
-	"I2C",
-	"ADC"
-    ],
-    "id": "RA4M1-CLICKER",
+    "features": [],
     "images": [
         "ra4m1_clicker_board.jpg",
         "ra4m1_clicker_pins.jpg"
     ],
-    "mcu": "RA4M1",
+    "mcu": "ra4m1",
     "product": "Mikroe RA4M1 Clicker",
     "thumbnail": "",
     "url": "https://www.mikroe.com/ra4m1-clicker",
diff --git a/ports/renesas-ra/boards/VK_RA6M5/board.json b/ports/renesas-ra/boards/VK_RA6M5/board.json
index ae11d52213..48371138b1 100644
--- a/ports/renesas-ra/boards/VK_RA6M5/board.json
+++ b/ports/renesas-ra/boards/VK_RA6M5/board.json
@@ -4,18 +4,12 @@
     ],
     "docs": "",
     "features": [
-        "UART",
-        "SPI",
-        "I2C",
-        "ADC",
-        "DAC",
-        "PWM"
+        "DAC"
     ],
-    "id": "VK-RA6M5",
     "images": [
         "VK-RA6M5.jpg"
     ],
-    "mcu": "RA6M5",
+    "mcu": "ra6m5",
     "product": "VK-RA6M5",
     "thumbnail": "",
     "url": "https://vekatech.com/VK-RA6M5_docs/brochures/VK-RA6M5%20Flyer%20R2.pdf",
diff --git a/ports/renesas-ra/boards/make-pins.py b/ports/renesas-ra/boards/make-pins.py
index 1b4588f02f..5147d27940 100644
--- a/ports/renesas-ra/boards/make-pins.py
+++ b/ports/renesas-ra/boards/make-pins.py
@@ -220,13 +220,7 @@ class Pins(object):
             for named_pin in self.board_pins:
                 qstr_set |= set([named_pin.name()])
             for qstr in sorted(qstr_set):
-                cond_var = None
-                if qstr.startswith("AF"):
-                    af_words = qstr.split("_")
-                    cond_var = conditional_var(af_words[1])
-                    print_conditional_if(cond_var, file=qstr_file)
                 print("Q({})".format(qstr), file=qstr_file)
-                # print_conditional_endif(cond_var, file=qstr_file)
 
     def print_ad_hdr(self, ad_const_filename):
         with open(ad_const_filename, "wt") as ad_const_file:
diff --git a/ports/renesas-ra/mpthreadport.c b/ports/renesas-ra/mpthreadport.c
index ecdb268468..a7d85cfe32 100644
--- a/ports/renesas-ra/mpthreadport.c
+++ b/ports/renesas-ra/mpthreadport.c
@@ -54,7 +54,11 @@ void mp_thread_gc_others(void) {
     mp_thread_mutex_unlock(&thread_mutex);
 }
 
-void mp_thread_create(void *(*entry)(void *), void *arg, size_t *stack_size) {
+mp_uint_t mp_thread_get_id(void) {
+    return (uint32_t)pyb_thread_cur;
+}
+
+mp_uint_t mp_thread_create(void *(*entry)(void *), void *arg, size_t *stack_size) {
     if (*stack_size == 0) {
         *stack_size = 4096; // default stack size
     } else if (*stack_size < 2048) {
@@ -82,6 +86,8 @@ void mp_thread_create(void *(*entry)(void *), void *arg, size_t *stack_size) {
 
     // adjust stack_size to provide room to recover from hitting the limit
     *stack_size -= 1024;
+
+    return id;
 }
 
 void mp_thread_start(void) {
diff --git a/ports/rp2/CMakeLists.txt b/ports/rp2/CMakeLists.txt
index 4334a0aba9..7718697b43 100644
--- a/ports/rp2/CMakeLists.txt
+++ b/ports/rp2/CMakeLists.txt
@@ -26,7 +26,7 @@ set(MICROPY_PORT_DIR ${CMAKE_CURRENT_LIST_DIR})
 
 # Set the board if it's not already set.
 if(NOT MICROPY_BOARD)
-    set(MICROPY_BOARD PICO)
+    set(MICROPY_BOARD RPI_PICO)
 endif()
 
 # Set the board directory and check that it exists.
diff --git a/ports/rp2/Makefile b/ports/rp2/Makefile
index 4f5b4728ec..8399b9e98a 100644
--- a/ports/rp2/Makefile
+++ b/ports/rp2/Makefile
@@ -8,16 +8,25 @@ ifdef BOARD_DIR
 # the path as the board name.
 BOARD ?= $(notdir $(BOARD_DIR:/=))
 else
-# If not given on the command line, then default to PICO.
-BOARD ?= PICO
+# If not given on the command line, then default to RPI_PICO.
+BOARD ?= RPI_PICO
 BOARD_DIR ?= boards/$(BOARD)
 endif
 
 ifeq ($(wildcard $(BOARD_DIR)/.),)
+ifeq ($(findstring boards/PICO,$(BOARD_DIR)),boards/PICO)
+$(warning The PICO* boards have been renamed to RPI_PICO*)
+endif
 $(error Invalid BOARD specified: $(BOARD_DIR))
 endif
- 
+
+# If the build directory is not given, make it reflect the board name (and
+# optionally the board variant).
+ifneq ($(BOARD_VARIANT),)
+BUILD ?= build-$(BOARD)-$(BOARD_VARIANT)
+else
 BUILD ?= build-$(BOARD)
+endif
 
 $(VERBOSE)MAKESILENT = -s
 
@@ -36,7 +45,7 @@ CMAKE_ARGS += -DCMAKE_BUILD_TYPE=Debug
 endif
 
 ifdef BOARD_VARIANT
-CMAKE_ARGS += -DBOARD_VARIANT=${BOARD_VARIANT}
+CMAKE_ARGS += -DMICROPY_BOARD_VARIANT=$(BOARD_VARIANT)
 endif
 
 HELP_BUILD_ERROR ?= "See \033[1;31mhttps://github.com/micropython/micropython/wiki/Build-Troubleshooting\033[0m"
@@ -50,13 +59,13 @@ clean:
 
 # First ensure that pico-sdk is initialised, then use cmake to pick everything
 # else (including board-specific dependencies).
+# Running the build with ECHO_SUBMODULES set will trigger py/mkrules.cmake to
+# print out the value of the GIT_SUBMODULES variable, prefixed with
+# "GIT_SUBMODULES", and then abort. This extracts out that line from the cmake
+# output and passes the list of submodules to py/mkrules.mk which does the
+# `git submodule init` on each.
 submodules:
 	$(MAKE) -f ../../py/mkrules.mk GIT_SUBMODULES="lib/pico-sdk" submodules
-	GIT_SUBMODULES=$$(cmake -B $(BUILD)/submodules -DECHO_SUBMODULES=1 ${CMAKE_ARGS} -S . 2>&1 | \
+	@GIT_SUBMODULES=$$(cmake -B $(BUILD)/submodules -DECHO_SUBMODULES=1 ${CMAKE_ARGS} -S . 2>&1 | \
 	                  grep '^GIT_SUBMODULES=' | cut -d= -f2); \
 	$(MAKE) -f ../../py/mkrules.mk GIT_SUBMODULES="$${GIT_SUBMODULES}" submodules
-
-query-variants:
-	@BOARD_VARIANTS=$$(cmake -B $(BUILD)/variants -DECHO_BOARD_VARIANTS=1 ${CMAKE_ARGS} -S . 2>&1 | \
-	                  grep '^BOARD_VARIANTS=' | cut -d= -f2); \
-	echo "VARIANTS: $${BOARD_VARIANTS}"
diff --git a/ports/rp2/boards/ADAFRUIT_FEATHER_RP2040/board.json b/ports/rp2/boards/ADAFRUIT_FEATHER_RP2040/board.json
index a7db469389..be63f4430b 100644
--- a/ports/rp2/boards/ADAFRUIT_FEATHER_RP2040/board.json
+++ b/ports/rp2/boards/ADAFRUIT_FEATHER_RP2040/board.json
@@ -5,11 +5,11 @@
     "docs": "",
     "features": [
         "Battery Charging",
-        "Breadboard Friendly",
+        "Dual-core",
+        "External Flash",
         "Feather",
+        "JST-SH",
         "RGB LED",
-        "SPI Flash",
-        "STEMMA QT/QWIIC",
         "USB-C"
     ],
     "images": [
diff --git a/ports/rp2/boards/ADAFRUIT_ITSYBITSY_RP2040/board.json b/ports/rp2/boards/ADAFRUIT_ITSYBITSY_RP2040/board.json
index 7ca0db0698..ea9070e13c 100644
--- a/ports/rp2/boards/ADAFRUIT_ITSYBITSY_RP2040/board.json
+++ b/ports/rp2/boards/ADAFRUIT_ITSYBITSY_RP2040/board.json
@@ -4,10 +4,10 @@
     ],
     "docs": "",
     "features": [
-        "Breadboard Friendly",
-        "Micro USB",
+        "Dual-core",
+        "External Flash",
         "RGB LED",
-        "SPI Flash"
+        "USB"
     ],
     "images": [
         "4888-05.jpg"
diff --git a/ports/rp2/boards/ADAFRUIT_QTPY_RP2040/board.json b/ports/rp2/boards/ADAFRUIT_QTPY_RP2040/board.json
index d63166616f..d5e4394f4e 100644
--- a/ports/rp2/boards/ADAFRUIT_QTPY_RP2040/board.json
+++ b/ports/rp2/boards/ADAFRUIT_QTPY_RP2040/board.json
@@ -4,11 +4,10 @@
     ],
     "docs": "",
     "features": [
-        "Breadboard Friendly",
-        "Castellated Pads",
+        "Dual-core",
+        "External Flash",
+        "JST-SH",
         "RGB LED",
-        "SPI Flash",
-        "STEMMA QT/QWIIC",
         "USB-C"
     ],
     "images": [
diff --git a/ports/rp2/boards/ARDUINO_NANO_RP2040_CONNECT/board.json b/ports/rp2/boards/ARDUINO_NANO_RP2040_CONNECT/board.json
index 5bd03e1e0b..5639aaa2a4 100644
--- a/ports/rp2/boards/ARDUINO_NANO_RP2040_CONNECT/board.json
+++ b/ports/rp2/boards/ARDUINO_NANO_RP2040_CONNECT/board.json
@@ -4,15 +4,14 @@
     ],
     "docs": "",
     "features": [
-        "Breadboard Friendly",
-        "Castellated Pads",
-        "WiFi Nina-W102",
-        "Bluetooth Nina-W102",
-        "IMU LSM6DSOXTR",
-        "Crypto IC ATECC608A-MAHDA-T",
-        "Microphone MP34DT05",
-        "SPI Flash 16MB",
-        "USB-MICRO"
+        "BLE",
+        "Dual-core",
+        "External Flash",
+        "IMU",
+        "Microphone",
+        "Secure Element",
+        "USB",
+        "WiFi"
     ],
     "images": [
         "ABX00052_01.iso_999x750.jpg"
diff --git a/ports/rp2/boards/GARATRONIC_PYBSTICK26_RP2040/board.json b/ports/rp2/boards/GARATRONIC_PYBSTICK26_RP2040/board.json
index 1b9e113143..df9dd5d0de 100644
--- a/ports/rp2/boards/GARATRONIC_PYBSTICK26_RP2040/board.json
+++ b/ports/rp2/boards/GARATRONIC_PYBSTICK26_RP2040/board.json
@@ -4,12 +4,10 @@
     ],
     "docs": "",
     "features": [
-        "USB Stick form factor",
-        "Breadboard Friendly",
-        "Reset/User button",
-        "Red/green/orange/blue leds",
-        "1MB SPI Flash",
-        "USB-A"
+        "Dual-core",
+        "External Flash",
+        "RGB LED",
+        "USB"
     ],
     "images": [
         "pybstick-rp2040-26-broches-micropython-c.jpg"
diff --git a/ports/rp2/boards/NULLBITS_BIT_C_PRO/board.json b/ports/rp2/boards/NULLBITS_BIT_C_PRO/board.json
index 2aff0580d8..08aa7068ef 100644
--- a/ports/rp2/boards/NULLBITS_BIT_C_PRO/board.json
+++ b/ports/rp2/boards/NULLBITS_BIT_C_PRO/board.json
@@ -4,10 +4,10 @@
     ],
     "docs": "",
     "features": [
-        "Breadboard Friendly",
+        "Dual-core",
+        "External Flash",
         "RGB LED",
-        "USB-C",
-        "SPI Flash"
+        "USB-C"
     ],
     "images": [
         "nullbits_bit_c_pro.jpg"
diff --git a/ports/rp2/boards/PIMORONI_PICOLIPO_16MB/board.json b/ports/rp2/boards/PIMORONI_PICOLIPO_16MB/board.json
index 9121154d81..c44ea55514 100644
--- a/ports/rp2/boards/PIMORONI_PICOLIPO_16MB/board.json
+++ b/ports/rp2/boards/PIMORONI_PICOLIPO_16MB/board.json
@@ -5,10 +5,9 @@
     "docs": "",
     "features": [
         "Battery Charging",
-        "Breadboard Friendly",
-        "Castellated Pads",
-        "SPI Flash",
-        "STEMMA QT/QWIIC",
+        "Dual-core",
+        "External Flash",
+        "JST-SH",
         "USB-C"
     ],
     "images": [
diff --git a/ports/rp2/boards/PIMORONI_PICOLIPO_4MB/board.json b/ports/rp2/boards/PIMORONI_PICOLIPO_4MB/board.json
index 69d8532397..cb06c746b6 100644
--- a/ports/rp2/boards/PIMORONI_PICOLIPO_4MB/board.json
+++ b/ports/rp2/boards/PIMORONI_PICOLIPO_4MB/board.json
@@ -5,10 +5,9 @@
     "docs": "",
     "features": [
         "Battery Charging",
-        "Breadboard Friendly",
-        "Castellated Pads",
-        "SPI Flash",
-        "STEMMA QT/QWIIC",
+        "Dual-core",
+        "External Flash",
+        "JST-SH",
         "USB-C"
     ],
     "images": [
diff --git a/ports/rp2/boards/PIMORONI_TINY2040/board.json b/ports/rp2/boards/PIMORONI_TINY2040/board.json
index 753a25beae..207647f6b2 100644
--- a/ports/rp2/boards/PIMORONI_TINY2040/board.json
+++ b/ports/rp2/boards/PIMORONI_TINY2040/board.json
@@ -4,8 +4,8 @@
     ],
     "docs": "",
     "features": [
-        "Breadboard Friendly",
-        "Castellated Pads",
+        "Dual-core",
+        "External Flash",
         "RGB LED",
         "USB-C"
     ],
diff --git a/ports/rp2/boards/PICO/board.json b/ports/rp2/boards/RPI_PICO/board.json
similarity index 74%
rename from ports/rp2/boards/PICO/board.json
rename to ports/rp2/boards/RPI_PICO/board.json
index 9abf505e54..07938978f3 100644
--- a/ports/rp2/boards/PICO/board.json
+++ b/ports/rp2/boards/RPI_PICO/board.json
@@ -4,11 +4,10 @@
     ],
     "docs": "",
     "features": [
-        "Breadboard friendly",
-        "Castellated Pads",
-        "Micro USB"
+        "Dual-core",
+        "External Flash",
+        "USB"
     ],
-    "id": "rp2-pico",
     "images": [
         "rp2-pico.jpg"
     ],
diff --git a/ports/rp2/boards/PICO/mpconfigboard.cmake b/ports/rp2/boards/RPI_PICO/mpconfigboard.cmake
similarity index 60%
rename from ports/rp2/boards/PICO/mpconfigboard.cmake
rename to ports/rp2/boards/RPI_PICO/mpconfigboard.cmake
index 3a40ca2871..13269e81e5 100644
--- a/ports/rp2/boards/PICO/mpconfigboard.cmake
+++ b/ports/rp2/boards/RPI_PICO/mpconfigboard.cmake
@@ -1 +1,2 @@
 # cmake file for Raspberry Pi Pico
+set(PICO_BOARD "pico")
diff --git a/ports/rp2/boards/PICO/mpconfigboard.h b/ports/rp2/boards/RPI_PICO/mpconfigboard.h
similarity index 100%
rename from ports/rp2/boards/PICO/mpconfigboard.h
rename to ports/rp2/boards/RPI_PICO/mpconfigboard.h
diff --git a/ports/rp2/boards/PICO/pins.csv b/ports/rp2/boards/RPI_PICO/pins.csv
similarity index 100%
rename from ports/rp2/boards/PICO/pins.csv
rename to ports/rp2/boards/RPI_PICO/pins.csv
diff --git a/ports/rp2/boards/PICO_W/board.json b/ports/rp2/boards/RPI_PICO_W/board.json
similarity index 68%
rename from ports/rp2/boards/PICO_W/board.json
rename to ports/rp2/boards/RPI_PICO_W/board.json
index a85d7e0446..6ea326c6cd 100644
--- a/ports/rp2/boards/PICO_W/board.json
+++ b/ports/rp2/boards/RPI_PICO_W/board.json
@@ -4,13 +4,12 @@
     ],
     "docs": "",
     "features": [
-        "Breadboard friendly",
-        "Castellated Pads",
-        "Micro USB",
-        "WiFi",
-        "Bluetooth"
+        "BLE",
+        "Dual-core",
+        "External Flash",
+        "USB",
+        "WiFi"
     ],
-    "id": "rp2-pico-w",
     "images": [
         "rp2-pico-w.jpg"
     ],
diff --git a/ports/rp2/boards/PICO_W/manifest.py b/ports/rp2/boards/RPI_PICO_W/manifest.py
similarity index 100%
rename from ports/rp2/boards/PICO_W/manifest.py
rename to ports/rp2/boards/RPI_PICO_W/manifest.py
diff --git a/ports/rp2/boards/PICO_W/mpconfigboard.cmake b/ports/rp2/boards/RPI_PICO_W/mpconfigboard.cmake
similarity index 93%
rename from ports/rp2/boards/PICO_W/mpconfigboard.cmake
rename to ports/rp2/boards/RPI_PICO_W/mpconfigboard.cmake
index e6db8dda6a..5610c313e6 100644
--- a/ports/rp2/boards/PICO_W/mpconfigboard.cmake
+++ b/ports/rp2/boards/RPI_PICO_W/mpconfigboard.cmake
@@ -1,5 +1,7 @@
 # cmake file for Raspberry Pi Pico W
 
+set(PICO_BOARD "pico_w")
+
 # The C malloc is needed by cyw43-driver Bluetooth
 set(MICROPY_C_HEAP_SIZE 4096)
 
diff --git a/ports/rp2/boards/PICO_W/mpconfigboard.h b/ports/rp2/boards/RPI_PICO_W/mpconfigboard.h
similarity index 100%
rename from ports/rp2/boards/PICO_W/mpconfigboard.h
rename to ports/rp2/boards/RPI_PICO_W/mpconfigboard.h
diff --git a/ports/rp2/boards/PICO_W/pins.csv b/ports/rp2/boards/RPI_PICO_W/pins.csv
similarity index 100%
rename from ports/rp2/boards/PICO_W/pins.csv
rename to ports/rp2/boards/RPI_PICO_W/pins.csv
diff --git a/ports/rp2/boards/SPARKFUN_PROMICRO/board.json b/ports/rp2/boards/SPARKFUN_PROMICRO/board.json
index a0d39165af..46878a29cd 100644
--- a/ports/rp2/boards/SPARKFUN_PROMICRO/board.json
+++ b/ports/rp2/boards/SPARKFUN_PROMICRO/board.json
@@ -4,10 +4,10 @@
     ],
     "docs": "",
     "features": [
-        "Breadboard Friendly",
-        "Castellated Pads",
+        "Dual-core",
+        "External Flash",
+        "JST-SH",
         "RGB LED",
-        "STEMMA QT/QWIIC",
         "USB-C"
     ],
     "images": [
diff --git a/ports/rp2/boards/SPARKFUN_THINGPLUS/board.json b/ports/rp2/boards/SPARKFUN_THINGPLUS/board.json
index 871a411b5b..3eeb397265 100644
--- a/ports/rp2/boards/SPARKFUN_THINGPLUS/board.json
+++ b/ports/rp2/boards/SPARKFUN_THINGPLUS/board.json
@@ -5,13 +5,13 @@
     "docs": "",
     "features": [
         "Battery Charging",
-        "Breadboard Friendly",
+        "Dual-core",
+        "External Flash",
         "Feather",
-        "MicroSD",
+        "JST-SH",
         "RGB LED",
-        "SPI Flash",
-        "STEMMA QT/QWIIC",
-        "USB-C"
+        "USB-C",
+        "microSD"
     ],
     "images": [
         "17745-SparkFun_Thing_Plus_-_RP2040-01a.jpg"
diff --git a/ports/rp2/boards/W5100S_EVB_PICO/board.json b/ports/rp2/boards/W5100S_EVB_PICO/board.json
index 4091b78433..daaf1cf8ac 100644
--- a/ports/rp2/boards/W5100S_EVB_PICO/board.json
+++ b/ports/rp2/boards/W5100S_EVB_PICO/board.json
@@ -4,10 +4,10 @@
     ],
     "docs": "",
     "features": [
-        "Breadboard Friendly",
-        "Castellated Pads",
+        "Dual-core",
         "Ethernet",
-        "Micro USB"
+        "External Flash",
+        "USB"
     ],
     "images": [
         "W5100S-EVB-Pico.jpg"
diff --git a/ports/rp2/boards/W5500_EVB_PICO/board.json b/ports/rp2/boards/W5500_EVB_PICO/board.json
index 90b3186cd6..9359825559 100644
--- a/ports/rp2/boards/W5500_EVB_PICO/board.json
+++ b/ports/rp2/boards/W5500_EVB_PICO/board.json
@@ -4,10 +4,10 @@
     ],
     "docs": "",
     "features": [
-        "Breadboard Friendly",
-        "Castellated Pads",
+        "Dual-core",
         "Ethernet",
-        "Micro USB"
+        "External Flash",
+        "USB"
     ],
     "images": [
         "W5500-EVB-Pico.jpg"
diff --git a/ports/rp2/boards/WEACTSTUDIO/README.md b/ports/rp2/boards/WEACTSTUDIO/README.md
index ae0acfd2c7..1d55350900 100644
--- a/ports/rp2/boards/WEACTSTUDIO/README.md
+++ b/ports/rp2/boards/WEACTSTUDIO/README.md
@@ -9,18 +9,15 @@ repository containing information on the board.
 
 ## Build notes
 
-Builds can be configured with the `BOARD_VARIANT` parameter. Valid variants
-can be displayed with the `query-variant` target. An example:
+By default the firmware supports boards with 16MiB flash. This can be
+configured using the `BOARD_VARIANT` parameter. The valid options are
+`FLASH_2M`, 'FLASH_4M', and 'FLASH_8M'.
 
 ```bash
 > cd ports/rp2
-> make BOARD=WEACTSTUDIO query-variants
-VARIANTS: flash_2mb flash_4mb flash_8mb flash_16mb
-> make BOARD=WEACTSTUDIO BOARD_VARIANT=flash_8mb submodules all  # Build the 8 MiB variant
+> make BOARD=WEACTSTUDIO BOARD_VARIANT=FLASH_8M submodules all  # Build the 8 MiB variant
 ```
 
-`flash_16mb` is the default if `BOARD_VARIANT` is not supplied.
-
 ## Board-specific modules
 
 The `board` module contains definitions for the onboard LED and user button.
diff --git a/ports/rp2/boards/WEACTSTUDIO/board.json b/ports/rp2/boards/WEACTSTUDIO/board.json
index bac5263627..223bbdc07b 100644
--- a/ports/rp2/boards/WEACTSTUDIO/board.json
+++ b/ports/rp2/boards/WEACTSTUDIO/board.json
@@ -4,8 +4,8 @@
     ],
     "docs": "",
     "features": [
-        "Breadboard Friendly",
-        "SPI Flash",
+        "Dual-core",
+        "External Flash",
         "USB-C"
     ],
     "images": [
@@ -15,9 +15,9 @@
     "product": "WeAct Studio RP2040",
     "url": "https://github.com/WeActTC/WeActStudio.RP2040CoreBoard",
     "variants": {
-        "flash_2mb": "2 MiB Flash",
-        "flash_4mb": "4 MiB Flash",
-        "flash_8mb": "8 MiB Flash"
+        "FLASH_2MB": "2 MiB Flash",
+        "FLASH_4MB": "4 MiB Flash",
+        "FLASH_8MB": "8 MiB Flash"
     },
     "vendor": "WeAct"
 }
diff --git a/ports/rp2/boards/WEACTSTUDIO/mpconfigboard.cmake b/ports/rp2/boards/WEACTSTUDIO/mpconfigboard.cmake
index 5fd3eec897..848b50f604 100644
--- a/ports/rp2/boards/WEACTSTUDIO/mpconfigboard.cmake
+++ b/ports/rp2/boards/WEACTSTUDIO/mpconfigboard.cmake
@@ -7,20 +7,18 @@ list(APPEND PICO_BOARD_HEADER_DIRS ${MICROPY_BOARD_DIR})
 # Freeze board.py
 set(MICROPY_FROZEN_MANIFEST ${MICROPY_BOARD_DIR}/manifest.py)
 
-# Provide different variants for the downloads page
-set(BOARD_VARIANTS "flash_2mb flash_4mb flash_8mb flash_16mb")
-
 # Select the 16MB variant as the default
-set(PICO_BOARD "weactstudio_16mb")
+set(PICO_BOARD "weactstudio_16MiB")
 
-if("${BOARD_VARIANT}" STREQUAL "flash_2mb")
-    set(PICO_BOARD "weactstudio_2mb")
+# Provide different variants for the downloads page
+if(MICROPY_BOARD_VARIANT STREQUAL "FLASH_2M")
+    set(PICO_BOARD "weactstudio_2MiB")
 endif()
 
-if("${BOARD_VARIANT}" STREQUAL "flash_4mb")
-set(PICO_BOARD "weactstudio_4mb")
+if(MICROPY_BOARD_VARIANT STREQUAL "FLASH_4M")
+    set(PICO_BOARD "weactstudio_4MiB")
 endif()
 
-if("${BOARD_VARIANT}" STREQUAL "flash_8mb")
-set(PICO_BOARD "weactstudio_8mb")
+if(MICROPY_BOARD_VARIANT STREQUAL "FLASH_8M")
+    set(PICO_BOARD "weactstudio_8MiB")
 endif()
diff --git a/ports/rp2/boards/WEACTSTUDIO/weactstudio_16mb.h b/ports/rp2/boards/WEACTSTUDIO/weactstudio_16MiB.h
similarity index 100%
rename from ports/rp2/boards/WEACTSTUDIO/weactstudio_16mb.h
rename to ports/rp2/boards/WEACTSTUDIO/weactstudio_16MiB.h
diff --git a/ports/rp2/boards/WEACTSTUDIO/weactstudio_2mb.h b/ports/rp2/boards/WEACTSTUDIO/weactstudio_2MiB.h
similarity index 100%
rename from ports/rp2/boards/WEACTSTUDIO/weactstudio_2mb.h
rename to ports/rp2/boards/WEACTSTUDIO/weactstudio_2MiB.h
diff --git a/ports/rp2/boards/WEACTSTUDIO/weactstudio_4mb.h b/ports/rp2/boards/WEACTSTUDIO/weactstudio_4MiB.h
similarity index 100%
rename from ports/rp2/boards/WEACTSTUDIO/weactstudio_4mb.h
rename to ports/rp2/boards/WEACTSTUDIO/weactstudio_4MiB.h
diff --git a/ports/rp2/boards/WEACTSTUDIO/weactstudio_8mb.h b/ports/rp2/boards/WEACTSTUDIO/weactstudio_8MiB.h
similarity index 100%
rename from ports/rp2/boards/WEACTSTUDIO/weactstudio_8mb.h
rename to ports/rp2/boards/WEACTSTUDIO/weactstudio_8MiB.h
diff --git a/ports/rp2/machine_timer.c b/ports/rp2/machine_timer.c
index e4fbb03af4..f0df541e6b 100644
--- a/ports/rp2/machine_timer.c
+++ b/ports/rp2/machine_timer.c
@@ -57,7 +57,12 @@ STATIC int64_t alarm_callback(alarm_id_t id, void *user_data) {
 STATIC void machine_timer_print(const mp_print_t *print, mp_obj_t self_in, mp_print_kind_t kind) {
     machine_timer_obj_t *self = MP_OBJ_TO_PTR(self_in);
     qstr mode = self->mode == TIMER_MODE_ONE_SHOT ? MP_QSTR_ONE_SHOT : MP_QSTR_PERIODIC;
-    mp_printf(print, "Timer(mode=%q, period=%u, tick_hz=1000000)", mode, self->delta_us);
+    mp_printf(print, "Timer(mode=%q, tick_hz=1000000, period=", mode);
+    if (self->delta_us <= 0xffffffff) {
+        mp_printf(print, "%u)", (uint32_t)self->delta_us);
+    } else {
+        mp_printf(print, "%u000)", (uint32_t)(self->delta_us / 1000));
+    }
 }
 
 STATIC mp_obj_t machine_timer_init_helper(machine_timer_obj_t *self, size_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
diff --git a/ports/rp2/mpthreadport.c b/ports/rp2/mpthreadport.c
index 33dc698305..ed9e338da7 100644
--- a/ports/rp2/mpthreadport.c
+++ b/ports/rp2/mpthreadport.c
@@ -116,7 +116,13 @@ STATIC void core1_entry_wrapper(void) {
     // returning from here will loop the core forever (WFI)
 }
 
-void mp_thread_create(void *(*entry)(void *), void *arg, size_t *stack_size) {
+mp_uint_t mp_thread_get_id(void) {
+    // On RP2, there are only two threads, one for each core, so the thread id
+    // is the core number.
+    return get_core_num();
+}
+
+mp_uint_t mp_thread_create(void *(*entry)(void *), void *arg, size_t *stack_size) {
     // Check if core1 is already in use.
     if (core1_entry != NULL) {
         mp_raise_msg(&mp_type_OSError, MP_ERROR_TEXT("core1 in use"));
@@ -144,6 +150,8 @@ void mp_thread_create(void *(*entry)(void *), void *arg, size_t *stack_size) {
 
     // Adjust stack_size to provide room to recover from hitting the limit.
     *stack_size -= 512;
+
+    return 1;
 }
 
 void mp_thread_start(void) {
diff --git a/ports/samd/boards/ADAFRUIT_FEATHER_M0_EXPRESS/board.json b/ports/samd/boards/ADAFRUIT_FEATHER_M0_EXPRESS/board.json
index b0cb02cd4f..22a9ffccba 100644
--- a/ports/samd/boards/ADAFRUIT_FEATHER_M0_EXPRESS/board.json
+++ b/ports/samd/boards/ADAFRUIT_FEATHER_M0_EXPRESS/board.json
@@ -5,11 +5,10 @@
     "docs": "",
     "features": [
         "Battery Charging",
-        "Breadboard Friendly",
+        "External Flash",
         "Feather",
-        "Micro USB",
         "RGB LED",
-        "SPI Flash"
+        "USB"
     ],
     "images": [
         "feather_m0_express.jpg"
diff --git a/ports/samd/boards/ADAFRUIT_FEATHER_M4_EXPRESS/board.json b/ports/samd/boards/ADAFRUIT_FEATHER_M4_EXPRESS/board.json
index c8042aa254..06cd9a4fe4 100644
--- a/ports/samd/boards/ADAFRUIT_FEATHER_M4_EXPRESS/board.json
+++ b/ports/samd/boards/ADAFRUIT_FEATHER_M4_EXPRESS/board.json
@@ -5,11 +5,10 @@
     "docs": "",
     "features": [
         "Battery Charging",
-        "Breadboard Friendly",
+        "External Flash",
         "Feather",
-        "Micro USB",
         "RGB LED",
-        "SPI Flash"
+        "USB"
     ],
     "images": [
         "feather_m4_express.jpg"
diff --git a/ports/samd/boards/ADAFRUIT_ITSYBITSY_M0_EXPRESS/board.json b/ports/samd/boards/ADAFRUIT_ITSYBITSY_M0_EXPRESS/board.json
index f99d19ca87..0e423b2b8e 100644
--- a/ports/samd/boards/ADAFRUIT_ITSYBITSY_M0_EXPRESS/board.json
+++ b/ports/samd/boards/ADAFRUIT_ITSYBITSY_M0_EXPRESS/board.json
@@ -4,10 +4,9 @@
     ],
     "docs": "",
     "features": [
-        "Breadboard Friendly",
-        "Micro USB",
+        "External Flash",
         "RGB LED",
-        "SPI Flash"
+        "USB"
     ],
     "images": [
         "itsybitsy_m0_express.jpg"
diff --git a/ports/samd/boards/ADAFRUIT_ITSYBITSY_M4_EXPRESS/board.json b/ports/samd/boards/ADAFRUIT_ITSYBITSY_M4_EXPRESS/board.json
index 83db285b4d..a998529ccd 100644
--- a/ports/samd/boards/ADAFRUIT_ITSYBITSY_M4_EXPRESS/board.json
+++ b/ports/samd/boards/ADAFRUIT_ITSYBITSY_M4_EXPRESS/board.json
@@ -4,10 +4,9 @@
     ],
     "docs": "",
     "features": [
-        "Breadboard Friendly",
-        "Micro USB",
+        "External Flash",
         "RGB LED",
-        "SPI Flash"
+        "USB"
     ],
     "images": [
         "itsybitsy_m4_express.jpg"
diff --git a/ports/samd/boards/ADAFRUIT_METRO_M4_EXPRESS/board.json b/ports/samd/boards/ADAFRUIT_METRO_M4_EXPRESS/board.json
index e0a256cf88..f830ff223f 100644
--- a/ports/samd/boards/ADAFRUIT_METRO_M4_EXPRESS/board.json
+++ b/ports/samd/boards/ADAFRUIT_METRO_M4_EXPRESS/board.json
@@ -4,14 +4,12 @@
     ],
     "docs": "",
     "features": [
-        "Micro USB",
-        "ADC",
-        "DAC",
-        "RGB LED",
-        "QSPI Flash",
-        "WiFi",
         "BLE",
-        "JLink"
+        "DAC",
+        "External Flash",
+        "RGB LED",
+        "USB",
+        "WiFi"
     ],
     "images": [
         "metro_m4_express_airlift.jpg"
diff --git a/ports/samd/boards/ADAFRUIT_METRO_M4_EXPRESS/mpconfigboard.mk b/ports/samd/boards/ADAFRUIT_METRO_M4_EXPRESS/mpconfigboard.mk
index 1a2635f7af..43ca5a59cc 100644
--- a/ports/samd/boards/ADAFRUIT_METRO_M4_EXPRESS/mpconfigboard.mk
+++ b/ports/samd/boards/ADAFRUIT_METRO_M4_EXPRESS/mpconfigboard.mk
@@ -7,5 +7,4 @@ TEXT0 = 0x4000
 MICROPY_PY_NETWORK ?= 1
 MICROPY_PY_NETWORK_NINAW10 ?= 1
 
-BOARD_VARIANTS += "wlan"
 MICROPY_HW_CODESIZE ?= 496K
diff --git a/ports/samd/boards/ADAFRUIT_TRINKET_M0/board.json b/ports/samd/boards/ADAFRUIT_TRINKET_M0/board.json
index 9112bc06ef..d77282db01 100644
--- a/ports/samd/boards/ADAFRUIT_TRINKET_M0/board.json
+++ b/ports/samd/boards/ADAFRUIT_TRINKET_M0/board.json
@@ -4,9 +4,8 @@
     ],
     "docs": "",
     "features": [
-        "Breadboard Friendly",
-        "Micro USB",
-        "RGB LED"
+        "RGB LED",
+        "USB"
     ],
     "images": [
         "trinket_m0.jpg"
diff --git a/ports/samd/boards/MINISAM_M4/board.json b/ports/samd/boards/MINISAM_M4/board.json
index 126e036400..6489dae863 100644
--- a/ports/samd/boards/MINISAM_M4/board.json
+++ b/ports/samd/boards/MINISAM_M4/board.json
@@ -4,9 +4,9 @@
     ],
     "docs": "",
     "features": [
-        "Micro USB",
+        "External Flash",
         "RGB LED",
-        "SPI Flash"
+        "USB"
     ],
     "images": [
         "mini_sam_m4.jpg"
diff --git a/ports/samd/boards/SAMD21_XPLAINED_PRO/board.json b/ports/samd/boards/SAMD21_XPLAINED_PRO/board.json
index 4d22c42bad..c59ebc1b7b 100644
--- a/ports/samd/boards/SAMD21_XPLAINED_PRO/board.json
+++ b/ports/samd/boards/SAMD21_XPLAINED_PRO/board.json
@@ -4,10 +4,12 @@
     ],
     "docs": "",
     "features": [
-        "Micro USB",
-        "SPI Flash"
+        "External Flash",
+        "USB"
+    ],
+    "images": [
+        "2033-atsamd21-xpro.jpg"
     ],
-    "images": ["2033-atsamd21-xpro.jpg"],
     "mcu": "samd21",
     "product": "SAMD21 Xplained Pro",
     "thumbnail": "",
diff --git a/ports/samd/boards/SEEED_WIO_TERMINAL/board.json b/ports/samd/boards/SEEED_WIO_TERMINAL/board.json
index 350ada4c4a..5300b03808 100644
--- a/ports/samd/boards/SEEED_WIO_TERMINAL/board.json
+++ b/ports/samd/boards/SEEED_WIO_TERMINAL/board.json
@@ -4,14 +4,17 @@
     ],
     "docs": "",
     "features": [
-        "USB-C",
-        "Display",
-        "Grove",
-        "WiFi",
         "BLE",
-        "SDCard"
+        "Display",
+        "External Flash",
+        "JST-PH",
+        "SDCard",
+        "USB-C",
+        "WiFi"
+    ],
+    "images": [
+        "wio-terminal.jpg"
     ],
-    "images": ["wio-terminal.jpg"],
     "mcu": "samd51",
     "product": "Wio Terminal D51R",
     "thumbnail": "",
diff --git a/ports/samd/boards/SEEED_XIAO_SAMD21/board.json b/ports/samd/boards/SEEED_XIAO_SAMD21/board.json
index 4e6217e19e..4d19f6b945 100644
--- a/ports/samd/boards/SEEED_XIAO_SAMD21/board.json
+++ b/ports/samd/boards/SEEED_XIAO_SAMD21/board.json
@@ -6,7 +6,9 @@
     "features": [
         "USB-C"
     ],
-    "images": ["seeeduino-xiao.jpg"],
+    "images": [
+        "seeeduino-xiao.jpg"
+    ],
     "mcu": "samd21",
     "product": "Seeeduino XIAO (SAMD21)",
     "thumbnail": "",
diff --git a/ports/samd/boards/SPARKFUN_SAMD51_THING_PLUS/board.json b/ports/samd/boards/SPARKFUN_SAMD51_THING_PLUS/board.json
index af643f5c5f..ee9ca9d368 100644
--- a/ports/samd/boards/SPARKFUN_SAMD51_THING_PLUS/board.json
+++ b/ports/samd/boards/SPARKFUN_SAMD51_THING_PLUS/board.json
@@ -5,10 +5,9 @@
     "docs": "",
     "features": [
         "Battery Charging",
-        "Breadboard Friendly",
-        "Micro USB",
-        "QWIIC",
-        "SPI Flash"
+        "External Flash",
+        "JST-SH",
+        "USB"
     ],
     "images": [
         "sparkfun_samd51_thing_plus.jpg"
diff --git a/ports/samd/modules/_boot.py b/ports/samd/modules/_boot.py
index 1ff51de598..93522e2ea3 100644
--- a/ports/samd/modules/_boot.py
+++ b/ports/samd/modules/_boot.py
@@ -1,6 +1,7 @@
 import gc
 import os
 import samd
+import sys
 
 bdev = samd.Flash()
 
@@ -13,7 +14,8 @@ except:
     fs_type.mkfs(bdev, progsize=256)
     vfs = fs_type(bdev, progsize=256)
 os.mount(vfs, "/")
+sys.path.append("/lib")
 
-del vfs, fs_type, bdev, os, samd
+del vfs, fs_type, bdev, os, samd, sys
 gc.collect()
 del gc
diff --git a/ports/stm32/Makefile b/ports/stm32/Makefile
index 81a48249e8..475d8f1004 100644
--- a/ports/stm32/Makefile
+++ b/ports/stm32/Makefile
@@ -13,8 +13,13 @@ ifeq ($(wildcard $(BOARD_DIR)/.),)
 $(error Invalid BOARD specified: $(BOARD_DIR))
 endif
 
-# If the build directory is not given, make it reflect the board name.
+# If the build directory is not given, make it reflect the board name (and
+# optionally the board variant).
+ifneq ($(BOARD_VARIANT),)
+BUILD ?= build-$(BOARD)-$(BOARD_VARIANT)
+else
 BUILD ?= build-$(BOARD)
+endif
 
 include ../../py/mkenv.mk
 -include mpconfigport.mk
@@ -43,9 +48,6 @@ include $(TOP)/extmod/extmod.mk
 
 GIT_SUBMODULES += lib/libhydrogen lib/stm32lib
 
-query-variants:
-	$(ECHO) "VARIANTS:" $(BOARD_VARIANTS)
-
 LD_DIR=boards
 USBDEV_DIR=usbdev
 #USBHOST_DIR=usbhost
@@ -358,6 +360,7 @@ SRC_C += \
 	dac.c \
 	adc.c \
 	sdio.c \
+	subghz.c \
 	$(wildcard $(BOARD_DIR)/*.c)
 
 SRC_O += \
diff --git a/ports/stm32/boards/ARDUINO_GIGA/board.json b/ports/stm32/boards/ARDUINO_GIGA/board.json
index f0595d4ad5..53c636c774 100644
--- a/ports/stm32/boards/ARDUINO_GIGA/board.json
+++ b/ports/stm32/boards/ARDUINO_GIGA/board.json
@@ -4,11 +4,12 @@
     ],
     "docs": "",
     "features": [
-        "8MB SDRAM",
-        "16MB Flash",
-        "Dual-core processor",
-        "USB Full speed",
-        "CYW43 WiFi/BT Module"
+        "BLE",
+        "Dual-core",
+        "External Flash",
+        "External RAM",
+        "USB",
+        "WiFi"
     ],
     "images": [
         "ABX00063_01.front_1000x750.jpg"
diff --git a/ports/stm32/boards/ARDUINO_NICLA_VISION/board.json b/ports/stm32/boards/ARDUINO_NICLA_VISION/board.json
index 801bc320b5..a4c81d69d4 100644
--- a/ports/stm32/boards/ARDUINO_NICLA_VISION/board.json
+++ b/ports/stm32/boards/ARDUINO_NICLA_VISION/board.json
@@ -4,11 +4,12 @@
     ],
     "docs": "",
     "features": [
-        "16MB Flash",
-        "Dual-core processor",
-        "USB High Speed Phy",
-        "CYW43 WiFi/BT Module",
-        "NXP SE050 crypto device"
+        "BLE",
+        "Dual-core",
+        "External Flash",
+        "Secure Element",
+        "USB",
+        "WiFi"
     ],
     "images": [
         "ABX00051_01.iso_1000x750.jpg"
diff --git a/ports/stm32/boards/ARDUINO_PORTENTA_H7/board.json b/ports/stm32/boards/ARDUINO_PORTENTA_H7/board.json
index 6467e43bb9..f39d7d4c47 100644
--- a/ports/stm32/boards/ARDUINO_PORTENTA_H7/board.json
+++ b/ports/stm32/boards/ARDUINO_PORTENTA_H7/board.json
@@ -4,14 +4,13 @@
     ],
     "docs": "",
     "features": [
-        "8MB SDRAM",
-        "16MB Flash",
-        "Dual-core processor",
-        "USB High Speed Phy",
-        "10/100 Ethernet Phy",
-        "CYW43 WiFi/BT Module",
-        "DisplayPort over USB-C",
-        "2x80 pin HD connectors"
+        "BLE",
+        "Dual-core",
+        "Ethernet",
+        "External Flash",
+        "External RAM",
+        "USB",
+        "WiFi"
     ],
     "images": [
         "ABX00042_01.iso_1000x750.jpg"
diff --git a/ports/stm32/boards/CERB40/board.json b/ports/stm32/boards/CERB40/board.json
index f80b3f5cab..e3bd4296ba 100644
--- a/ports/stm32/boards/CERB40/board.json
+++ b/ports/stm32/boards/CERB40/board.json
@@ -8,8 +8,8 @@
         "cerb40.jpg"
     ],
     "mcu": "stm32f4",
-    "product": "CERB40",
+    "product": "Cerb40",
     "thumbnail": "",
     "url": "",
-    "vendor": ""
+    "vendor": "Fez"
 }
diff --git a/ports/stm32/boards/HYDRABUS/board.json b/ports/stm32/boards/HYDRABUS/board.json
index 32561e6525..20a2ac5eae 100644
--- a/ports/stm32/boards/HYDRABUS/board.json
+++ b/ports/stm32/boards/HYDRABUS/board.json
@@ -8,8 +8,8 @@
         "hydrabus.jpg"
     ],
     "mcu": "stm32f4",
-    "product": "HYDRABUS",
+    "product": "HydraBus v1.0",
     "thumbnail": "",
     "url": "",
-    "vendor": ""
+    "vendor": "HydraBus"
 }
diff --git a/ports/stm32/boards/LEGO_HUB_NO6/board.json b/ports/stm32/boards/LEGO_HUB_NO6/board.json
index c11b9f1818..3c602abba1 100644
--- a/ports/stm32/boards/LEGO_HUB_NO6/board.json
+++ b/ports/stm32/boards/LEGO_HUB_NO6/board.json
@@ -9,5 +9,5 @@
     "product": "Hub No.6",
     "thumbnail": "",
     "url": "",
-    "vendor": "Lego"
+    "vendor": "LEGO"
 }
diff --git a/ports/stm32/boards/LIMIFROG/board.json b/ports/stm32/boards/LIMIFROG/board.json
index 3137350074..f516963a5b 100644
--- a/ports/stm32/boards/LIMIFROG/board.json
+++ b/ports/stm32/boards/LIMIFROG/board.json
@@ -8,8 +8,8 @@
         "limifrog.jpg"
     ],
     "mcu": "stm32l4",
-    "product": "LIMIFROG",
+    "product": "LimiFrog",
     "thumbnail": "",
     "url": "",
-    "vendor": ""
+    "vendor": "LimiFrog"
 }
diff --git a/ports/stm32/boards/MIKROE_QUAIL/board.json b/ports/stm32/boards/MIKROE_QUAIL/board.json
index ccd9b4fdc0..689bdb1052 100644
--- a/ports/stm32/boards/MIKROE_QUAIL/board.json
+++ b/ports/stm32/boards/MIKROE_QUAIL/board.json
@@ -6,9 +6,8 @@
     "features": [
         "mikroBUS"
     ],
-    "id": "MIKROE-QUAIL",
     "images": [
-            "quail_top.jpg"
+        "quail_top.jpg"
     ],
     "mcu": "stm32f4",
     "product": "MikroE Quail",
diff --git a/ports/stm32/boards/NETDUINO_PLUS_2/board.json b/ports/stm32/boards/NETDUINO_PLUS_2/board.json
index 044bc2736b..603032ee98 100644
--- a/ports/stm32/boards/NETDUINO_PLUS_2/board.json
+++ b/ports/stm32/boards/NETDUINO_PLUS_2/board.json
@@ -8,8 +8,8 @@
         "netduino_plus_2.jpg"
     ],
     "mcu": "stm32f4",
-    "product": "NETDUINO_PLUS_2",
+    "product": "Netduino Plus 2",
     "thumbnail": "",
     "url": "",
-    "vendor": ""
+    "vendor": "Netduino"
 }
diff --git a/ports/stm32/boards/NUCLEO_WB55/rfcore_debug.py b/ports/stm32/boards/NUCLEO_WB55/rfcore_debug.py
index 4dbead0acc..db533f18dc 100644
--- a/ports/stm32/boards/NUCLEO_WB55/rfcore_debug.py
+++ b/ports/stm32/boards/NUCLEO_WB55/rfcore_debug.py
@@ -35,6 +35,7 @@
 # See rfcore_firmware.py for more information.
 
 from machine import mem8, mem16, mem32
+from micropython import const
 import stm
 
 SRAM2A_BASE = const(0x2003_0000)
diff --git a/ports/stm32/boards/NUCLEO_WL55/mpconfigboard.h b/ports/stm32/boards/NUCLEO_WL55/mpconfigboard.h
index 51700ba8a5..843e855ce7 100644
--- a/ports/stm32/boards/NUCLEO_WL55/mpconfigboard.h
+++ b/ports/stm32/boards/NUCLEO_WL55/mpconfigboard.h
@@ -14,7 +14,8 @@
 #define MICROPY_PY_SOCKET                       (0)
 #define MICROPY_PY_NETWORK                      (0)
 #define MICROPY_PY_ONEWIRE                      (0)
-#define MICROPY_PY_STM                          (0)
+#define MICROPY_PY_STM                          (1) // for subghz radio functions
+#define MICROPY_PY_STM_CONST                    (0) // saves size, no named registers
 #define MICROPY_PY_PYB_LEGACY                   (0)
 #define MICROPY_PY_HEAPQ                        (0)
 
@@ -28,6 +29,13 @@
 #define MICROPY_HW_RTC_USE_LSE                  (1)
 #define MICROPY_HW_RTC_USE_US                   (1)
 
+// Use external 32MHz TCXO + PLL as system clock source
+// (If unset, board will use the internal MSI oscillator instead.)
+#define MICROPY_HW_CLK_USE_HSE                  (1)
+
+// HSE bypass for STM32WL5x means TCXO is powered from PB0_VDDTCXO pin
+#define MICROPY_HW_CLK_USE_BYPASS               (1)
+
 // UART buses
 #define MICROPY_HW_UART1_TX                     (pin_B6)    // Arduino D1, pin 7 on CN9
 #define MICROPY_HW_UART1_RX                     (pin_B7)    // Arduino D0, pin 8 on CN9
@@ -48,6 +56,10 @@
 #define MICROPY_HW_SPI1_MISO                    (pin_A6)    // Arduino D12, pin 5 on CN5
 #define MICROPY_HW_SPI1_MOSI                    (pin_A7)    // Arduino D11, pin 4 on CN5
 
+// SUBGHZSPI Internal radio SPI BUS
+#define MICROPY_HW_SUBGHZSPI_NAME               "SUBGHZ"
+#define MICROPY_HW_SUBGHZSPI_ID                 3
+
 // User switch; pressing the button makes the input go low
 #define MICROPY_HW_USRSW_PIN                    (pin_A0)
 #define MICROPY_HW_USRSW_PULL                   (GPIO_PULLUP)
diff --git a/ports/stm32/boards/NUCLEO_WL55/pins.csv b/ports/stm32/boards/NUCLEO_WL55/pins.csv
index afcf34df11..41e2d725a2 100644
--- a/ports/stm32/boards/NUCLEO_WL55/pins.csv
+++ b/ports/stm32/boards/NUCLEO_WL55/pins.csv
@@ -14,7 +14,8 @@
 ,PA13
 ,PA14
 ,PA15
-,PB0
+# in the default board configuration, PB0 must stay muxed to analog for HSE VDDTCXO function
+,-PB0
 ,PB1
 ,PB2
 ,PB3
@@ -33,9 +34,9 @@
 ,PC0
 ,PC1
 ,PC2
-,PC3
-,PC4
-,PC5
+FE_CTRL3,PC3
+FE_CTRL1,PC4
+FE_CTRL2,PC5
 ,PC6
 SW,PA0
 SW1,PA0
diff --git a/ports/stm32/boards/PYBD_SF2/board.json b/ports/stm32/boards/PYBD_SF2/board.json
index 534a048ff0..06a83e4d89 100644
--- a/ports/stm32/boards/PYBD_SF2/board.json
+++ b/ports/stm32/boards/PYBD_SF2/board.json
@@ -4,7 +4,6 @@
     ],
     "docs": "",
     "features": [],
-    "id": "PYBD-SF2",
     "images": [
         "PYBD_SF2_W4F2.jpg",
         "PYBD_SF2_W4F2_top.jpg",
diff --git a/ports/stm32/boards/PYBD_SF3/board.json b/ports/stm32/boards/PYBD_SF3/board.json
index 3e4731b3d2..e89f268cff 100644
--- a/ports/stm32/boards/PYBD_SF3/board.json
+++ b/ports/stm32/boards/PYBD_SF3/board.json
@@ -4,7 +4,6 @@
     ],
     "docs": "",
     "features": [],
-    "id": "PYBD-SF3",
     "images": [
         "PYBD_SF3_W4F2.jpg",
         "PYBD_SF3_W4F2_top.jpg",
diff --git a/ports/stm32/boards/PYBD_SF6/board.json b/ports/stm32/boards/PYBD_SF6/board.json
index 3e689d69be..b6d85d6fd7 100644
--- a/ports/stm32/boards/PYBD_SF6/board.json
+++ b/ports/stm32/boards/PYBD_SF6/board.json
@@ -4,10 +4,9 @@
     ],
     "docs": "",
     "features": [
-        "WiFi",
-        "BLE"
+        "BLE",
+        "WiFi"
     ],
-    "id": "PYBD-SF6",
     "images": [
         "PYBD_SF6_W4F2.jpg",
         "PYBD_SF6_W4F2_top.jpg",
diff --git a/ports/stm32/boards/PYBLITEV10/board.json b/ports/stm32/boards/PYBLITEV10/board.json
index ce98ba7de7..0d2338d3db 100644
--- a/ports/stm32/boards/PYBLITEV10/board.json
+++ b/ports/stm32/boards/PYBLITEV10/board.json
@@ -4,7 +4,6 @@
     ],
     "docs": "",
     "features": [],
-    "id": "pyblitev10",
     "images": [
         "PYBLITEv1_0.jpg",
         "PYBLITEv1_0-B.jpg",
@@ -15,10 +14,10 @@
     "thumbnail": "",
     "url": "https://store.micropython.org/product/PYBLITEv1.0",
     "variants": {
-        "dp": "Double-precision float",
-        "dp-thread": "Double precision float + Threads",
-        "network": "Wiznet 5200 Driver",
-        "thread": "Threading"
+        "DP": "Double-precision float",
+        "DP_THREAD": "Double precision float + Threads",
+        "NETWORK": "Wiznet 5200 Driver",
+        "THREAD": "Threading"
     },
     "vendor": "George Robotics"
 }
diff --git a/ports/stm32/boards/PYBLITEV10/mpconfigboard.mk b/ports/stm32/boards/PYBLITEV10/mpconfigboard.mk
index 461886b63c..1fe609cbb5 100644
--- a/ports/stm32/boards/PYBLITEV10/mpconfigboard.mk
+++ b/ports/stm32/boards/PYBLITEV10/mpconfigboard.mk
@@ -6,22 +6,20 @@ TEXT0_ADDR = 0x08000000
 TEXT1_ADDR = 0x08020000
 
 # Provide different variants for the downloads page.
-BOARD_VARIANTS += "dp thread dp-thread network"
-
-ifeq ($(BOARD_VARIANT),dp)
+ifeq ($(BOARD_VARIANT),DP)
 MICROPY_FLOAT_IMPL=double
 endif
 
-ifeq ($(BOARD_VARIANT),thread)
+ifeq ($(BOARD_VARIANT),THREAD)
 CFLAGS += -DMICROPY_PY_THREAD=1
 endif
 
-ifeq ($(BOARD_VARIANT),dp-thread)
+ifeq ($(BOARD_VARIANT),DP_THREAD)
 MICROPY_FLOAT_IMPL=double
 CFLAGS += -DMICROPY_PY_THREAD=1
 endif
 
-ifeq ($(BOARD_VARIANT),network)
+ifeq ($(BOARD_VARIANT),NETWORK)
 MICROPY_PY_NETWORK_WIZNET5K=5200
 endif
 
diff --git a/ports/stm32/boards/PYBV10/board.json b/ports/stm32/boards/PYBV10/board.json
index 2907b8fc45..0c5fea2eb8 100644
--- a/ports/stm32/boards/PYBV10/board.json
+++ b/ports/stm32/boards/PYBV10/board.json
@@ -4,7 +4,6 @@
     ],
     "docs": "",
     "features": [],
-    "id": "pybv10",
     "images": [
         "PYBv1_0-C.jpg"
     ],
@@ -13,10 +12,10 @@
     "thumbnail": "",
     "url": "",
     "variants": {
-        "dp": "Double-precision float",
-        "dp-thread": "Double precision float + Threads",
-        "network": "Wiznet 5200 Driver",
-        "thread": "Threading"
+        "DP": "Double-precision float",
+        "DP_THREAD": "Double precision float + Threads",
+        "NETWORK": "Wiznet 5200 Driver",
+        "THREAD": "Threading"
     },
     "vendor": "George Robotics"
 }
diff --git a/ports/stm32/boards/PYBV10/mpconfigboard.mk b/ports/stm32/boards/PYBV10/mpconfigboard.mk
index 363f6b4806..1a4d676319 100644
--- a/ports/stm32/boards/PYBV10/mpconfigboard.mk
+++ b/ports/stm32/boards/PYBV10/mpconfigboard.mk
@@ -16,22 +16,20 @@ endif
 MICROPY_VFS_LFS2 = 1
 
 # Provide different variants for the downloads page.
-BOARD_VARIANTS += "dp thread dp-thread network"
-
-ifeq ($(BOARD_VARIANT),dp)
+ifeq ($(BOARD_VARIANT),DP)
 MICROPY_FLOAT_IMPL=double
 endif
 
-ifeq ($(BOARD_VARIANT),thread)
+ifeq ($(BOARD_VARIANT),THREAD)
 CFLAGS += -DMICROPY_PY_THREAD=1
 endif
 
-ifeq ($(BOARD_VARIANT),dp-thread)
+ifeq ($(BOARD_VARIANT),DP_THREAD)
 MICROPY_FLOAT_IMPL=double
 CFLAGS += -DMICROPY_PY_THREAD=1
 endif
 
-ifeq ($(BOARD_VARIANT),network)
+ifeq ($(BOARD_VARIANT),NETWORK)
 MICROPY_PY_NETWORK_WIZNET5K=5200
 endif
 
diff --git a/ports/stm32/boards/PYBV11/board.json b/ports/stm32/boards/PYBV11/board.json
index fe59a7b16d..5d7abbaa83 100644
--- a/ports/stm32/boards/PYBV11/board.json
+++ b/ports/stm32/boards/PYBV11/board.json
@@ -4,7 +4,6 @@
     ],
     "docs": "",
     "features": [],
-    "id": "pybv11",
     "images": [
         "PYBv1_1.jpg",
         "PYBv1_1-C.jpg",
@@ -15,10 +14,10 @@
     "thumbnail": "",
     "url": "https://store.micropython.org/product/PYBv1.1",
     "variants": {
-        "dp": "Double-precision float",
-        "dp-thread": "Double precision float + Threads",
-        "network": "Wiznet 5200 Driver",
-        "thread": "Threading"
+        "DP": "Double-precision float",
+        "DP_THREAD": "Double precision float + Threads",
+        "NETWORK": "Wiznet 5200 Driver",
+        "THREAD": "Threading"
     },
     "vendor": "George Robotics"
 }
diff --git a/ports/stm32/boards/PYBV11/mpconfigboard.mk b/ports/stm32/boards/PYBV11/mpconfigboard.mk
index 857049f215..6dcb2fd1b4 100644
--- a/ports/stm32/boards/PYBV11/mpconfigboard.mk
+++ b/ports/stm32/boards/PYBV11/mpconfigboard.mk
@@ -16,22 +16,20 @@ endif
 MICROPY_VFS_LFS2 = 1
 
 # Provide different variants for the downloads page.
-BOARD_VARIANTS += "dp thread dp-thread network"
-
-ifeq ($(BOARD_VARIANT),dp)
+ifeq ($(BOARD_VARIANT),DP)
 MICROPY_FLOAT_IMPL=double
 endif
 
-ifeq ($(BOARD_VARIANT),thread)
+ifeq ($(BOARD_VARIANT),THREAD)
 CFLAGS += -DMICROPY_PY_THREAD=1
 endif
 
-ifeq ($(BOARD_VARIANT),dp-thread)
+ifeq ($(BOARD_VARIANT),DP_THREAD)
 MICROPY_FLOAT_IMPL=double
 CFLAGS += -DMICROPY_PY_THREAD=1
 endif
 
-ifeq ($(BOARD_VARIANT),network)
+ifeq ($(BOARD_VARIANT),NETWORK)
 MICROPY_PY_NETWORK_WIZNET5K=5200
 endif
 
diff --git a/ports/stm32/boards/STM32F439/board.json b/ports/stm32/boards/STM32F439/board.json
index 140c3474ca..068a9022d7 100644
--- a/ports/stm32/boards/STM32F439/board.json
+++ b/ports/stm32/boards/STM32F439/board.json
@@ -11,5 +11,5 @@
     "product": "STM32F439",
     "thumbnail": "",
     "url": "",
-    "vendor": ""
+    "vendor": "ST Microelectronics"
 }
diff --git a/ports/stm32/boards/USBDONGLE_WB55/board.json b/ports/stm32/boards/USBDONGLE_WB55/board.json
index 858e94d105..6d61f0c280 100644
--- a/ports/stm32/boards/USBDONGLE_WB55/board.json
+++ b/ports/stm32/boards/USBDONGLE_WB55/board.json
@@ -11,5 +11,5 @@
     "product": "USBDONGLE_WB55",
     "thumbnail": "",
     "url": "",
-    "vendor": ""
+    "vendor": "ST Microelectronics"
 }
diff --git a/ports/stm32/cyw43_configport.h b/ports/stm32/cyw43_configport.h
index 4b6dde3c43..f2a880603a 100644
--- a/ports/stm32/cyw43_configport.h
+++ b/ports/stm32/cyw43_configport.h
@@ -93,6 +93,13 @@
 #define CYW43_PIN_WL_REG_ON             pyb_pin_WL_REG_ON
 #define CYW43_PIN_WL_HOST_WAKE          pyb_pin_WL_HOST_WAKE
 #define CYW43_PIN_WL_SDIO_1             pyb_pin_WL_SDIO_1
+#define CYW43_PIN_WL_GPIO_1             pyb_pin_WL_GPIO_1
+#define CYW43_PIN_WL_GPIO_4             pyb_pin_WL_GPIO_4
+
+#define CYW43_PIN_BT_REG_ON             pyb_pin_BT_REG_ON
+#define CYW43_PIN_BT_HOST_WAKE          pyb_pin_BT_HOST_WAKE
+#define CYW43_PIN_BT_DEV_WAKE           pyb_pin_BT_DEV_WAKE
+#define CYW43_PIN_BT_CTS                pyb_pin_BT_CTS
 
 #if MICROPY_HW_ENABLE_RF_SWITCH
 #define CYW43_PIN_WL_RFSW_VDD           pyb_pin_WL_RFSW_VDD
diff --git a/ports/stm32/dma.c b/ports/stm32/dma.c
index cdbb90e5d8..bfa4fb23ff 100644
--- a/ports/stm32/dma.c
+++ b/ports/stm32/dma.c
@@ -161,7 +161,7 @@ static const DMA_InitTypeDef dma_init_struct_i2s = {
 static const DMA_InitTypeDef dma_init_struct_sdio = {
     #if defined(STM32F4) || defined(STM32F7)
     .Channel = 0,
-    #elif defined(STM32G0) || defined(STM32G4) || defined(STM32L0) || defined(STM32L4) || defined(STM32WB)
+    #elif defined(STM32G0) || defined(STM32G4) || defined(STM32L0) || defined(STM32L4) || defined(STM32WB)) || defined(STM32WL)
     .Request = 0,
     #endif
     .Direction = 0,
@@ -171,7 +171,7 @@ static const DMA_InitTypeDef dma_init_struct_sdio = {
     .MemDataAlignment = DMA_MDATAALIGN_WORD,
     #if defined(STM32F4) || defined(STM32F7)
     .Mode = DMA_PFCTRL,
-    #elif defined(STM32G0) || defined(STM32G4) || defined(STM32L0) || defined(STM32L4) || defined(STM32WB)
+    #elif defined(STM32G0) || defined(STM32G4) || defined(STM32L0) || defined(STM32L4) || defined(STM32WB) || defined(STM32WL)
     .Mode = DMA_NORMAL,
     #endif
     .Priority = DMA_PRIORITY_VERY_HIGH,
@@ -189,7 +189,7 @@ static const DMA_InitTypeDef dma_init_struct_sdio = {
 static const DMA_InitTypeDef dma_init_struct_dac = {
     #if defined(STM32F4) || defined(STM32F7)
     .Channel = 0,
-    #elif defined(STM32G0) || defined(STM32G4) || defined(STM32H7) || defined(STM32L0) || defined(STM32L4) || defined(STM32WB)
+    #elif defined(STM32G0) || defined(STM32G4) || defined(STM32H7) || defined(STM32L0) || defined(STM32L4) || defined(STM32WB) || defined(STM32WL)
     .Request = 0,
     #endif
     .Direction = 0,
@@ -558,6 +558,10 @@ const dma_descr_t dma_SPI_1_RX = { DMA1_Channel1, DMA_REQUEST_SPI1_RX, dma_id_0,
 const dma_descr_t dma_SPI_1_TX = { DMA1_Channel2, DMA_REQUEST_SPI1_TX, dma_id_1, &dma_init_struct_spi_i2c };
 const dma_descr_t dma_SPI_2_RX = { DMA1_Channel3, DMA_REQUEST_SPI2_RX, dma_id_2, &dma_init_struct_spi_i2c };
 const dma_descr_t dma_SPI_2_TX = { DMA1_Channel4, DMA_REQUEST_SPI2_TX, dma_id_3, &dma_init_struct_spi_i2c };
+#if defined(STM32WL)
+const dma_descr_t dma_SPI_SUBGHZ_RX = { DMA1_Channel5, DMA_REQUEST_SUBGHZSPI_RX, dma_id_4, &dma_init_struct_spi_i2c };
+const dma_descr_t dma_SPI_SUBGHZ_TX = { DMA1_Channel6, DMA_REQUEST_SUBGHZSPI_TX, dma_id_5, &dma_init_struct_spi_i2c };
+#endif
 
 static const uint8_t dma_irqn[NSTREAM] = {
     DMA1_Channel1_IRQn,
@@ -1217,7 +1221,7 @@ void DMA1_Channel4_5_6_7_IRQHandler(void) {
     IRQ_EXIT(DMA1_Channel4_5_6_7_IRQn);
 }
 
-#elif defined(STM32L1) || defined(STM32L4) || defined(STM32WB)
+#elif defined(STM32L1) || defined(STM32L4) || defined(STM32WB) || defined(STM32WL)
 
 void DMA1_Channel1_IRQHandler(void) {
     IRQ_ENTER(DMA1_Channel1_IRQn);
@@ -1340,9 +1344,9 @@ static void dma_enable_clock(dma_id_t dma_id) {
     dma_enable_mask |= (1 << dma_id);
     MICROPY_END_ATOMIC_SECTION(irq_state);
 
-    #if defined(STM32WB)
-    // This MCU has a DMAMUX peripheral which needs to be enabled to multiplex the channels.
+    #if defined(STM32G4) || defined(STM32WB) || defined(STM32WL)
     if (!__HAL_RCC_DMAMUX1_IS_CLK_ENABLED()) {
+        // MCU has a DMAMUX peripheral which needs to be enabled to multiplex the channels.
         __HAL_RCC_DMAMUX1_CLK_ENABLE();
     }
     #endif
@@ -1350,9 +1354,6 @@ static void dma_enable_clock(dma_id_t dma_id) {
     if (dma_id < NSTREAMS_PER_CONTROLLER) {
         if (((old_enable_mask & DMA1_ENABLE_MASK) == 0) && !DMA1_IS_CLK_ENABLED()) {
             __HAL_RCC_DMA1_CLK_ENABLE();
-            #if defined(STM32G4)
-            __HAL_RCC_DMAMUX1_CLK_ENABLE();
-            #endif
 
             // We just turned on the clock. This means that anything stored
             // in dma_last_channel (for DMA1) needs to be invalidated.
@@ -1367,9 +1368,6 @@ static void dma_enable_clock(dma_id_t dma_id) {
         if (((old_enable_mask & DMA2_ENABLE_MASK) == 0) && !DMA2_IS_CLK_ENABLED()) {
             __HAL_RCC_DMA2_CLK_ENABLE();
 
-            #if defined(STM32G4)
-            __HAL_RCC_DMAMUX1_CLK_ENABLE();
-            #endif
             // We just turned on the clock. This means that anything stored
             // in dma_last_channel (for DMA2) needs to be invalidated.
 
diff --git a/ports/stm32/dma.h b/ports/stm32/dma.h
index 92d5db6c0a..2afc947541 100644
--- a/ports/stm32/dma.h
+++ b/ports/stm32/dma.h
@@ -136,6 +136,8 @@ extern const dma_descr_t dma_SPI_3_TX;
 extern const dma_descr_t dma_SDIO_0;
 extern const dma_descr_t dma_I2C_4_TX;
 extern const dma_descr_t dma_I2C_4_RX;
+extern const dma_descr_t dma_SPI_SUBGHZ_TX;
+extern const dma_descr_t dma_SPI_SUBGHZ_RX;
 
 #endif
 
diff --git a/ports/stm32/irq.h b/ports/stm32/irq.h
index 8e98b4cc5e..7f10d0d004 100644
--- a/ports/stm32/irq.h
+++ b/ports/stm32/irq.h
@@ -155,6 +155,8 @@ static inline void restore_irq_pri(uint32_t state) {
 
 #define IRQ_PRI_CAN             NVIC_EncodePriority(NVIC_PRIORITYGROUP_4, 7, 0)
 
+#define IRQ_PRI_SUBGHZ_RADIO    NVIC_EncodePriority(NVIC_PRIORITYGROUP_4, 8, 0)
+
 #define IRQ_PRI_SPI             NVIC_EncodePriority(NVIC_PRIORITYGROUP_4, 8, 0)
 
 // Interrupt priority for non-special timers.
diff --git a/ports/stm32/main.c b/ports/stm32/main.c
index 2235e4de35..95b74c621a 100644
--- a/ports/stm32/main.c
+++ b/ports/stm32/main.c
@@ -86,6 +86,7 @@
 #include "servo.h"
 #include "dac.h"
 #include "can.h"
+#include "subghz.h"
 
 #if MICROPY_PY_THREAD
 STATIC pyb_thread_t pyb_thread_main;
@@ -403,6 +404,9 @@ void stm32_main(uint32_t reset_mode) {
     #if defined(STM32WB)
     rfcore_init();
     #endif
+    #if defined(STM32WL)
+    subghz_init();
+    #endif
     #if MICROPY_HW_SDRAM_SIZE
     sdram_init();
     bool sdram_valid = true;
@@ -650,6 +654,9 @@ soft_reset_exit:
     #if MICROPY_PY_BLUETOOTH
     mp_bluetooth_deinit();
     #endif
+    #if defined(STM32WL)
+    subghz_deinit();
+    #endif
     #if MICROPY_PY_NETWORK
     mod_network_deinit();
     #endif
diff --git a/ports/stm32/make-stmconst.py b/ports/stm32/make-stmconst.py
index 49b5c1a17b..4e4f2d7155 100644
--- a/ports/stm32/make-stmconst.py
+++ b/ports/stm32/make-stmconst.py
@@ -319,10 +319,10 @@ def main():
     print("")
 
     with open(args.qstr_filename, "wt") as qstr_file:
-        print("#if MICROPY_PY_STM", file=qstr_file)
+        print("#if MICROPY_PY_STM_CONST", file=qstr_file)
         for qstr in sorted(needed_qstrs):
             print("Q({})".format(qstr), file=qstr_file)
-        print("#endif // MICROPY_PY_STM", file=qstr_file)
+        print("#endif // MICROPY_PY_STM_CONST", file=qstr_file)
 
     with open(args.mpz_filename, "wt") as mpz_file:
         for mpz in sorted(needed_mpzs):
diff --git a/ports/stm32/mboot/fwupdate.py b/ports/stm32/mboot/fwupdate.py
index 78a8d73658..47ceb19ba5 100644
--- a/ports/stm32/mboot/fwupdate.py
+++ b/ports/stm32/mboot/fwupdate.py
@@ -3,7 +3,7 @@
 
 from micropython import const
 import struct, time
-import zlib, machine, stm
+import deflate, machine, stm
 
 # Constants to be used with update_mpy
 VFS_FAT = 1
@@ -36,7 +36,7 @@ def dfu_read(filename):
     if hdr == b"Dfu":
         pass
     elif hdr == b"\x1f\x8b\x08":
-        f = zlib.DecompIO(f, 16 + 15)
+        f = deflate.DeflateIO(f, deflate.GZIP)
     else:
         print("Invalid firmware", filename)
         return None
@@ -231,7 +231,7 @@ def update_app_elements(
     # Check firmware is of .dfu or .dfu.gz type
     try:
         with open(filename, "rb") as f:
-            hdr = zlib.DecompIO(f, 16 + 15).read(6)
+            hdr = deflate.DeflateIO(f, deflate.GZIP).read(6)
     except Exception:
         with open(filename, "rb") as f:
             hdr = f.read(6)
diff --git a/ports/stm32/modstm.c b/ports/stm32/modstm.c
index 94d56d4d08..251360594a 100644
--- a/ports/stm32/modstm.c
+++ b/ports/stm32/modstm.c
@@ -32,6 +32,7 @@
 #include "extmod/machine_mem.h"
 #include "rfcore.h"
 #include "portmodules.h"
+#include "subghz.h"
 
 #if MICROPY_PY_STM
 
@@ -44,13 +45,21 @@ STATIC const mp_rom_map_elem_t stm_module_globals_table[] = {
     { MP_ROM_QSTR(MP_QSTR_mem16), MP_ROM_PTR(&machine_mem16_obj) },
     { MP_ROM_QSTR(MP_QSTR_mem32), MP_ROM_PTR(&machine_mem32_obj) },
 
+    #if MICROPY_PY_STM_CONST
     #include "genhdr/modstm_const.h"
+    #endif
 
     #if defined(STM32WB)
     { MP_ROM_QSTR(MP_QSTR_rfcore_status), MP_ROM_PTR(&rfcore_status_obj) },
     { MP_ROM_QSTR(MP_QSTR_rfcore_fw_version), MP_ROM_PTR(&rfcore_fw_version_obj) },
     { MP_ROM_QSTR(MP_QSTR_rfcore_sys_hci), MP_ROM_PTR(&rfcore_sys_hci_obj) },
     #endif
+
+    #if defined(STM32WL)
+    { MP_ROM_QSTR(MP_QSTR_subghz_cs), MP_ROM_PTR(&subghz_cs_obj) },
+    { MP_ROM_QSTR(MP_QSTR_subghz_irq), MP_ROM_PTR(&subghz_irq_obj) },
+    { MP_ROM_QSTR(MP_QSTR_subghz_is_busy), MP_ROM_PTR(&subghz_is_busy_obj) },
+    #endif
 };
 
 STATIC MP_DEFINE_CONST_DICT(stm_module_globals, stm_module_globals_table);
diff --git a/ports/stm32/mpconfigboard_common.h b/ports/stm32/mpconfigboard_common.h
index 149d2ae73a..611a08252d 100644
--- a/ports/stm32/mpconfigboard_common.h
+++ b/ports/stm32/mpconfigboard_common.h
@@ -32,11 +32,16 @@
 /*****************************************************************************/
 // Feature settings with defaults
 
-// Whether to include the stm module, with peripheral register constants
+// Whether to include the stm module
 #ifndef MICROPY_PY_STM
 #define MICROPY_PY_STM (1)
 #endif
 
+// Whether to include named register constants in the stm module
+#ifndef MICROPY_PY_STM_CONST
+#define MICROPY_PY_STM_CONST (MICROPY_PY_STM)
+#endif
+
 // Whether to include the pyb module
 #ifndef MICROPY_PY_PYB
 #define MICROPY_PY_PYB (1)
@@ -471,8 +476,12 @@
 #define MICROPY_HW_RCC_HSI_STATE (RCC_HSI_OFF)
 #define MICROPY_HW_RCC_FLAG_HSxRDY (RCC_FLAG_HSERDY)
 #if MICROPY_HW_CLK_USE_BYPASS
+#if !defined(STM32WL)
 #define MICROPY_HW_RCC_HSE_STATE (RCC_HSE_BYPASS)
 #else
+#define MICROPY_HW_RCC_HSE_STATE (RCC_HSE_BYPASS_PWR)
+#endif
+#else
 #define MICROPY_HW_RCC_HSE_STATE (RCC_HSE_ON)
 #endif
 #endif
diff --git a/ports/stm32/mpconfigport.h b/ports/stm32/mpconfigport.h
index 37165b1589..2d2d81486b 100644
--- a/ports/stm32/mpconfigport.h
+++ b/ports/stm32/mpconfigport.h
@@ -92,7 +92,6 @@
 #endif
 
 // extended modules
-#define MICROPY_PY_SSL_FINALISER    (MICROPY_PY_SSL)
 #define MICROPY_PY_HASHLIB_MD5      (MICROPY_PY_SSL)
 #define MICROPY_PY_HASHLIB_SHA1     (MICROPY_PY_SSL)
 #define MICROPY_PY_CRYPTOLIB        (MICROPY_PY_SSL)
diff --git a/ports/stm32/mpthreadport.c b/ports/stm32/mpthreadport.c
index ecdb268468..a7d85cfe32 100644
--- a/ports/stm32/mpthreadport.c
+++ b/ports/stm32/mpthreadport.c
@@ -54,7 +54,11 @@ void mp_thread_gc_others(void) {
     mp_thread_mutex_unlock(&thread_mutex);
 }
 
-void mp_thread_create(void *(*entry)(void *), void *arg, size_t *stack_size) {
+mp_uint_t mp_thread_get_id(void) {
+    return (uint32_t)pyb_thread_cur;
+}
+
+mp_uint_t mp_thread_create(void *(*entry)(void *), void *arg, size_t *stack_size) {
     if (*stack_size == 0) {
         *stack_size = 4096; // default stack size
     } else if (*stack_size < 2048) {
@@ -82,6 +86,8 @@ void mp_thread_create(void *(*entry)(void *), void *arg, size_t *stack_size) {
 
     // adjust stack_size to provide room to recover from hitting the limit
     *stack_size -= 1024;
+
+    return id;
 }
 
 void mp_thread_start(void) {
diff --git a/ports/stm32/powerctrlboot.c b/ports/stm32/powerctrlboot.c
index 51b740a809..b075073a5b 100644
--- a/ports/stm32/powerctrlboot.c
+++ b/ports/stm32/powerctrlboot.c
@@ -460,13 +460,71 @@ void SystemClock_Config(void) {
 #include "stm32wlxx_ll_utils.h"
 
 void SystemClock_Config(void) {
-    // Set flash latency
+    // Set flash latency (2 wait states, sysclk > 36MHz)
     LL_FLASH_SetLatency(LL_FLASH_LATENCY_2);
     while (LL_FLASH_GetLatency() != LL_FLASH_LATENCY_2) {
     }
 
     LL_PWR_SetRegulVoltageScaling(LL_PWR_REGU_VOLTAGE_SCALE1);
 
+    #if MICROPY_HW_CLK_USE_HSE
+    // Enable the 32MHz external oscillator and 48MHZ SYSCLK via PLL
+
+    #if MICROPY_HW_CLK_USE_BYPASS
+    // Use "bypass power" option, port PB0_VDDTCXO supplies TCXO
+    // (STM32WL5x has no other HSE bypass mode.)
+
+    // "PB0 must be configured in analog mode prior enabling the HSE"
+    //
+    // Note: PB0 analog mode muxes PB0_VDDTCXO pin to the VDDTCXO regulator, set
+    // to default voltage of 1.7V.  Changing this voltage requires initializing
+    // the SUBGHZ radio and sending a Set_Tcxo command to it.
+    //
+    // For the Nucelo-WL55 board, ST uses the NDK "NT2016SF-32M-END5875A" TCXO
+    // which has no publicly available datasheet. However, the ST code for this
+    // board always keeps the pin at the default 1.7V voltage level so changing
+    // the level would only be needed if a different TCXO is used.
+    //
+    // (Note also that setting pin PB0 as a push-pull GPIO output is technically
+    // possible too, but 3.3V will be too high for many TCXOs.)
+    mp_hal_pin_config(pin_B0, MP_HAL_PIN_MODE_ANALOG, MP_HAL_PIN_PULL_NONE, 0);
+
+    LL_RCC_HSE_EnableTcxo();
+
+    #endif // MICROPY_HW_CLK_USE_BYPASS
+
+    LL_RCC_HSE_Enable();
+    while (!LL_RCC_HSE_IsReady()) {
+        // Wait for HSE Ready signal
+    }
+
+    // Configure PLL for a 48MHz SYSCLK
+    #define PLLM (HSE_VALUE / 16000000) // VCO input 16MHz (recommended in ST docs)
+    #define PLLN (6) // 7*8MHz = 96MHz
+    #define PLLP (2) // f_P = 48MHz
+    #define PLLQ (2) // f_Q = 48MHz
+    #define PLLR (2) // f_R = 48MHz
+    RCC->PLLCFGR =
+        (PLLR - 1) << RCC_PLLCFGR_PLLR_Pos | RCC_PLLCFGR_PLLREN
+            | (PLLQ - 1) << RCC_PLLCFGR_PLLQ_Pos | RCC_PLLCFGR_PLLQEN
+            | (PLLP - 1) << RCC_PLLCFGR_PLLP_Pos | RCC_PLLCFGR_PLLPEN
+            | PLLN << RCC_PLLCFGR_PLLN_Pos
+            | (PLLM - 1) << RCC_PLLCFGR_PLLM_Pos
+            | LL_RCC_PLLSOURCE_HSE;
+
+    LL_RCC_PLL_Enable();
+    LL_RCC_PLL_EnableDomain_SYS();
+    while (!LL_RCC_PLL_IsReady()) {
+        // Wait for PLL to lock
+    }
+
+    LL_RCC_SetSysClkSource(LL_RCC_SYS_CLKSOURCE_PLL);
+    while (LL_RCC_GetSysClkSource() != LL_RCC_SYS_CLKSOURCE_STATUS_PLL) {
+        // Wait for system clock source to switch
+    }
+
+    #else // Use MSI as 48MHz source for SYSCLK
+
     // Enable MSI
     LL_RCC_MSI_Enable();
     while (!LL_RCC_MSI_IsReady()) {
@@ -482,6 +540,8 @@ void SystemClock_Config(void) {
     while (LL_RCC_GetSysClkSource() != LL_RCC_SYS_CLKSOURCE_STATUS_MSI) {
     }
 
+    #endif // MICROPY_HW_CLK_USE_HSE
+
     // Set bus dividers
     LL_RCC_SetAHBPrescaler(LL_RCC_SYSCLK_DIV_1);
     LL_RCC_SetAHB3Prescaler(LL_RCC_SYSCLK_DIV_1);
diff --git a/ports/stm32/spi.c b/ports/stm32/spi.c
index 11a9a74ea3..1f5996165e 100644
--- a/ports/stm32/spi.c
+++ b/ports/stm32/spi.c
@@ -62,6 +62,9 @@ STATIC SPI_HandleTypeDef SPIHandle5 = {.Instance = NULL};
 #if defined(MICROPY_HW_SPI6_SCK)
 STATIC SPI_HandleTypeDef SPIHandle6 = {.Instance = NULL};
 #endif
+#if defined(MICROPY_HW_SUBGHZSPI_ID)
+static SPI_HandleTypeDef SPIHandleSubGhz = {.Instance = NULL};
+#endif
 
 const spi_t spi_obj[6] = {
     #if defined(MICROPY_HW_SPI1_SCK)
@@ -76,6 +79,8 @@ const spi_t spi_obj[6] = {
     #endif
     #if defined(MICROPY_HW_SPI3_SCK)
     {&SPIHandle3, &dma_SPI_3_TX, &dma_SPI_3_RX},
+    #elif MICROPY_HW_SUBGHZSPI_ID == 3
+    {&SPIHandleSubGhz, &dma_SPI_SUBGHZ_TX, &dma_SPI_SUBGHZ_RX},
     #else
     {NULL, NULL, NULL},
     #endif
@@ -96,6 +101,10 @@ const spi_t spi_obj[6] = {
     #endif
 };
 
+#if defined(MICROPY_HW_SUBGHZSPI_ID) && MICROPY_HW_SUBGHZSPI_ID != 3
+#error "spi_obj needs updating for new value of MICROPY_HW_SUBGHZSPI_ID"
+#endif
+
 #if defined(STM32H5) || defined(STM32H7)
 // STM32H5/H7 HAL requires SPI IRQs to be enabled and handled.
 #if defined(MICROPY_HW_SPI1_SCK)
@@ -163,6 +172,9 @@ void spi_init0(void) {
     #if defined(MICROPY_HW_SPI6_SCK)
     SPIHandle6.Instance = SPI6;
     #endif
+    #if defined(MICROPY_HW_SUBGHZSPI_ID)
+    SPIHandleSubGhz.Instance = SUBGHZSPI;
+    #endif
 }
 
 int spi_find_index(mp_obj_t id) {
@@ -195,6 +207,10 @@ int spi_find_index(mp_obj_t id) {
         } else if (strcmp(port, MICROPY_HW_SPI6_NAME) == 0) {
             spi_id = 6;
         #endif
+        #ifdef MICROPY_HW_SUBGHZSPI_NAME
+        } else if (strcmp(port, MICROPY_HW_SUBGHZSPI_NAME) == 0) {
+            spi_id = MICROPY_HW_SUBGHZSPI_ID;
+        #endif
         } else {
             mp_raise_msg_varg(&mp_type_ValueError, MP_ERROR_TEXT("SPI(%s) doesn't exist"), port);
         }
@@ -239,7 +255,7 @@ STATIC uint32_t spi_get_source_freq(SPI_HandleTypeDef *spi) {
     } else {
         return HAL_RCCEx_GetPeriphCLKFreq(RCC_PERIPHCLK_SPI6);
     }
-    #else
+    #else // !STM32F0, !STM32G0, !STM32H
     #if defined(SPI2)
     if (spi->Instance == SPI2) {
         // SPI2 is on APB1
@@ -252,11 +268,20 @@ STATIC uint32_t spi_get_source_freq(SPI_HandleTypeDef *spi) {
         return HAL_RCC_GetPCLK1Freq();
     } else
     #endif
+    #if defined(MICROPY_HW_SUBGHZSPI_ID)
+    if (spi->Instance == SUBGHZSPI) {
+        // In STM32WL5x, SUBGHZSPI is PCLK3 which is same as HCLK3, no HCLK3->PCLK3 divider exists in clock tree
+        #if !defined(LL_APB3_GRP1_PERIPH_SUBGHZSPI)
+        #error "SPI needs updating for new SUBGHZSPI clock configuration"
+        #endif
+        return HAL_RCC_GetHCLK3Freq();
+    } else
+    #endif
     {
         // SPI1, SPI4, SPI5 and SPI6 are on APB2
         return HAL_RCC_GetPCLK2Freq();
     }
-    #endif
+    #endif // STM32F0, STM32G0, STM32H
 }
 
 // sets the parameters in the SPI_InitTypeDef struct
@@ -411,6 +436,12 @@ int spi_init(const spi_t *self, bool enable_nss_pin) {
         // enable the SPI clock
         __HAL_RCC_SPI6_CLK_ENABLE();
     #endif
+    #if defined(MICROPY_HW_SUBGHZSPI_ID)
+    } else if (spi->Instance == SUBGHZSPI) {
+        irqn = SUBGHZSPI_IRQn;
+        // pins remain all NULL, internal bus has no GPIO mappings
+        __HAL_RCC_SUBGHZSPI_CLK_ENABLE();
+    #endif
     } else {
         // SPI does not exist for this board (shouldn't get here, should be checked by caller)
         return -MP_EINVAL;
@@ -502,6 +533,14 @@ void spi_deinit(const spi_t *spi_obj) {
         __HAL_RCC_SPI6_CLK_DISABLE();
         HAL_NVIC_DisableIRQ(SPI6_IRQn);
     #endif
+    #if defined(MICROPY_HW_SUBGHZSPI_ID)
+    } else if (spi->Instance == SUBGHZSPI) {
+        __HAL_RCC_SUBGHZSPI_FORCE_RESET();
+        __HAL_RCC_SUBGHZSPI_RELEASE_RESET();
+        __HAL_RCC_SUBGHZSPI_CLK_DISABLE();
+        HAL_NVIC_DisableIRQ(SUBGHZSPI_IRQn);
+
+    #endif
     }
 }
 
@@ -661,6 +700,11 @@ void spi_print(const mp_print_t *print, const spi_t *spi_obj, bool legacy) {
         spi_num = 6;
     }
     #endif
+    #if defined(MICROPY_HW_SUBGHZSPI_ID)
+    else if (spi->Instance == SUBGHZSPI) {
+        spi_num = MICROPY_HW_SUBGHZSPI_ID;
+    }
+    #endif
 
     mp_printf(print, "SPI(%u", spi_num);
     if (spi->State != HAL_SPI_STATE_RESET) {
diff --git a/ports/stm32/subghz.c b/ports/stm32/subghz.c
new file mode 100644
index 0000000000..1daed59aaf
--- /dev/null
+++ b/ports/stm32/subghz.c
@@ -0,0 +1,139 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2023 Angus Gratton
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include "py/gc.h"
+#include "py/runtime.h"
+#include "subghz.h"
+#include "irq.h"
+#include "spi.h"
+
+#if defined(STM32WL)
+
+// Interface to the STM32WL series "SUBGHZ Radio" module
+
+STATIC void handle_radio_irq() {
+    // Level-triggered interrupts means the interrupt has to be cleared before
+    // this function returns.
+    //
+    // Rather than writing to SUBGHZ SPI in Interrupt Context to clear the
+    // interrupt, disable the IRQ and rely on Python code to call
+    // subghz_irq(handler) to re-enable when needed.
+    HAL_NVIC_DisableIRQ(SUBGHZ_Radio_IRQn);
+
+    mp_obj_t callback = MP_STATE_PORT(subghz_callback);
+    if (callback != mp_const_none) {
+        mp_sched_lock();
+        gc_lock();
+        // Passing dummy 'pin' argument of None, to keep
+        // compatibility with machine.Pin.isr() handlers
+        mp_call_function_1_protected(callback, mp_const_none);
+        gc_unlock();
+        mp_sched_unlock();
+    }
+}
+
+void SUBGHZ_Radio_IRQHandler(void) {
+    IRQ_ENTER(SUBGHZ_Radio_IRQn);
+    handle_radio_irq();
+    IRQ_EXIT(SUBGHZ_Radio_IRQn);
+}
+
+void subghz_init(void) {
+    __HAL_RCC_SUBGHZ_RADIO_FORCE_RESET();
+
+    #if !MICROPY_HW_CLK_USE_HSE && MICROPY_HW_CLK_USE_BYPASS
+    // SUBGHZ clock source is HSE oscillator.
+    //
+    // If this is not already enabled for the system clock, and we're depending
+    // on the VDDTCXO pin to power the HSE ("bypass mode"), then enable it.
+    __HAL_RCC_HSE_CONFIG(RCC_HSE_BYPASS_PWR);
+    #endif
+
+    NVIC_DisableIRQ(SUBGHZ_Radio_IRQn);
+    NVIC_SetPriority(SUBGHZ_Radio_IRQn, IRQ_PRI_SUBGHZ_RADIO);
+
+    __HAL_RCC_SUBGHZ_RADIO_RELEASE_RESET();
+
+    while (__HAL_RCC_GET_FLAG(RCC_FLAG_RFRST) != 0) {
+    }
+
+    MP_STATE_PORT(subghz_callback) = mp_const_none;
+}
+
+void subghz_deinit(void) {
+    MP_STATE_PORT(subghz_callback) = mp_const_none;
+    NVIC_DisableIRQ(SUBGHZ_Radio_IRQn);
+    __HAL_RCC_SUBGHZ_RADIO_FORCE_RESET();
+    __HAL_RCC_SUBGHZ_RADIO_RELEASE_RESET();
+}
+
+STATIC mp_obj_t subghz_cs(mp_obj_t value) {
+    // Treat the same as normal SPI - truthy is "unselected",
+    //   falsey is active low "selected",
+    if (mp_obj_is_true(value)) {
+        LL_PWR_UnselectSUBGHZSPI_NSS();
+    } else {
+        LL_PWR_SelectSUBGHZSPI_NSS();
+    }
+
+    return mp_const_none;
+}
+MP_DEFINE_CONST_FUN_OBJ_1(subghz_cs_obj, subghz_cs);
+
+STATIC mp_obj_t subghz_irq(mp_obj_t handler) {
+    MP_STATE_PORT(subghz_callback) = handler;
+
+    if (mp_obj_is_true(handler)) {
+        HAL_NVIC_ClearPendingIRQ(SUBGHZ_Radio_IRQn);
+        HAL_NVIC_EnableIRQ(SUBGHZ_Radio_IRQn);
+    } else {
+        HAL_NVIC_DisableIRQ(SUBGHZ_Radio_IRQn);
+    }
+
+    return mp_const_none;
+}
+MP_DEFINE_CONST_FUN_OBJ_1(subghz_irq_obj, subghz_irq);
+
+STATIC mp_obj_t subghz_is_busy(void) {
+    // Read the raw unmasked busy signal. This should be checked before driving
+    // CS low to start a command.
+    //
+    // Reads the raw RFBUSYS not the masked RFBUSYMS, in contradiction to EM0453
+    // 6.3 "Radio busy management". This is because the RFBUSYMS signal doesn't
+    // seem to match the reference manual. Observed behaviour matches this bug
+    // report instead: https://community.st.com/s/question/0D53W000014zFx9SAE
+    //
+    // Reading RFBUSYS won't cause any problems here provided a new SPI command
+    // isn't immediately after the previous command, which shouldn't be possible
+    // with MicroPython.
+    return mp_obj_new_bool(LL_PWR_IsActiveFlag_RFBUSYS());
+
+}
+MP_DEFINE_CONST_FUN_OBJ_0(subghz_is_busy_obj, subghz_is_busy);
+
+MP_REGISTER_ROOT_POINTER(mp_obj_t subghz_callback);
+
+#endif // STM32WL
diff --git a/ports/stm32/subghz.h b/ports/stm32/subghz.h
new file mode 100644
index 0000000000..f8678cd087
--- /dev/null
+++ b/ports/stm32/subghz.h
@@ -0,0 +1,40 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2023 Angus Gratton
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+#ifndef MICROPY_INCLUDED_STM32_SUBGHZ_H
+#define MICROPY_INCLUDED_STM32_SUBGHZ_H
+
+#include "py/obj.h"
+
+// Interface to the STM32WL series "SUBGHZ Radio" module
+
+void subghz_init(void);
+void subghz_deinit(void);
+
+MP_DECLARE_CONST_FUN_OBJ_1(subghz_cs_obj);
+MP_DECLARE_CONST_FUN_OBJ_1(subghz_irq_obj);
+MP_DECLARE_CONST_FUN_OBJ_0(subghz_is_busy_obj);
+
+#endif
diff --git a/ports/stm32/uart.c b/ports/stm32/uart.c
index e477c5c16c..7a2a3a9580 100644
--- a/ports/stm32/uart.c
+++ b/ports/stm32/uart.c
@@ -1052,12 +1052,20 @@ size_t uart_tx_data(pyb_uart_obj_t *self, const void *src_in, size_t num_chars,
         // the overall timeout rather than the character timeout.
         timeout = self->timeout;
     } else {
+        #if defined(STM32G4)
+        // With using UART FIFO, the timeout should be long enough that FIFO becomes empty.
+        // Since previous data transfer may be ongoing, the timeout must be multiplied
+        // timeout_char by FIFO size + 1.
+        // STM32G4 has 8 words FIFO.
+        timeout = (8 + 1) * self->timeout_char;
+        #else
         // The timeout specified here is for waiting for the TX data register to
         // become empty (ie between chars), as well as for the final char to be
         // completely transferred.  The default value for timeout_char is long
         // enough for 1 char, but we need to double it to wait for the last char
         // to be transferred to the data register, and then to be transmitted.
         timeout = 2 * self->timeout_char;
+        #endif
     }
 
     const uint8_t *src = (const uint8_t *)src_in;
diff --git a/ports/unix/Makefile b/ports/unix/Makefile
index 188e4be633..eae02bf257 100644
--- a/ports/unix/Makefile
+++ b/ports/unix/Makefile
@@ -201,7 +201,6 @@ SRC_C += \
 	mpthreadport.c \
 	input.c \
 	modmachine.c \
-	modselect.c \
 	alloc.c \
 	fatfs_port.c \
 	mpbthciport.c \
diff --git a/ports/unix/modjni.c b/ports/unix/modjni.c
index 10622f588f..a1cfca8149 100644
--- a/ports/unix/modjni.c
+++ b/ports/unix/modjni.c
@@ -329,8 +329,7 @@ STATIC MP_DEFINE_CONST_OBJ_TYPE(
     unary_op, jobject_unary_op,
     attr, jobject_attr,
     subscr, jobject_subscr,
-    iter, subscr_getiter,
-    //    .locals_dict = &jobject_locals_dict,
+    iter, subscr_getiter
     );
 
 STATIC mp_obj_t new_jobject(jobject jo) {
@@ -574,9 +573,7 @@ STATIC MP_DEFINE_CONST_OBJ_TYPE(
     MP_QSTR_jmethod,
     MP_TYPE_FLAG_NONE,
     print, jmethod_print,
-    call, jmethod_call,
-    //    .attr = jobject_attr,
-    //    .locals_dict = &jobject_locals_dict,
+    call, jmethod_call
     );
 
 #ifdef __ANDROID__
@@ -615,26 +612,26 @@ STATIC void create_jvm(void) {
 
     jclass Object_class = JJ(FindClass, "java/lang/Object");
     Object_toString_mid = JJ(GetMethodID, Object_class, "toString",
-        MP_ERROR_TEXT("()Ljava/lang/String;"));
+        MP_COMPRESSED_ROM_TEXT("()Ljava/lang/String;"));
 
     Class_getName_mid = (*env)->GetMethodID(env, Class_class, "getName",
-        MP_ERROR_TEXT("()Ljava/lang/String;"));
+        MP_COMPRESSED_ROM_TEXT("()Ljava/lang/String;"));
     Class_getField_mid = (*env)->GetMethodID(env, Class_class, "getField",
-        MP_ERROR_TEXT("(Ljava/lang/String;)Ljava/lang/reflect/Field;"));
+        MP_COMPRESSED_ROM_TEXT("(Ljava/lang/String;)Ljava/lang/reflect/Field;"));
     Class_getMethods_mid = (*env)->GetMethodID(env, Class_class, "getMethods",
-        MP_ERROR_TEXT("()[Ljava/lang/reflect/Method;"));
+        MP_COMPRESSED_ROM_TEXT("()[Ljava/lang/reflect/Method;"));
     Class_getConstructors_mid = (*env)->GetMethodID(env, Class_class, "getConstructors",
-        MP_ERROR_TEXT("()[Ljava/lang/reflect/Constructor;"));
+        MP_COMPRESSED_ROM_TEXT("()[Ljava/lang/reflect/Constructor;"));
     Method_getName_mid = (*env)->GetMethodID(env, method_class, "getName",
-        MP_ERROR_TEXT("()Ljava/lang/String;"));
+        MP_COMPRESSED_ROM_TEXT("()Ljava/lang/String;"));
 
     List_class = JJ(FindClass, "java/util/List");
     List_get_mid = JJ(GetMethodID, List_class, "get",
-        MP_ERROR_TEXT("(I)Ljava/lang/Object;"));
+        MP_COMPRESSED_ROM_TEXT("(I)Ljava/lang/Object;"));
     List_set_mid = JJ(GetMethodID, List_class, "set",
-        MP_ERROR_TEXT("(ILjava/lang/Object;)Ljava/lang/Object;"));
+        MP_COMPRESSED_ROM_TEXT("(ILjava/lang/Object;)Ljava/lang/Object;"));
     List_size_mid = JJ(GetMethodID, List_class, "size",
-        MP_ERROR_TEXT("()I"));
+        MP_COMPRESSED_ROM_TEXT("()I"));
     IndexException_class = JJ(FindClass, "java/lang/IndexOutOfBoundsException");
 }
 
diff --git a/ports/unix/modselect.c b/ports/unix/modselect.c
deleted file mode 100644
index 894820c63d..0000000000
--- a/ports/unix/modselect.c
+++ /dev/null
@@ -1,356 +0,0 @@
-/*
- * This file is part of the MicroPython project, http://micropython.org/
- *
- * The MIT License (MIT)
- *
- * Copyright (c) 2014 Damien P. George
- * Copyright (c) 2015-2017 Paul Sokolovsky
- *
- * Permission is hereby granted, free of charge, to any person obtaining a copy
- * of this software and associated documentation files (the "Software"), to deal
- * in the Software without restriction, including without limitation the rights
- * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
- * copies of the Software, and to permit persons to whom the Software is
- * furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included in
- * all copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
- * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
- * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
- * THE SOFTWARE.
- */
-
-#include "py/mpconfig.h"
-
-#if MICROPY_PY_SELECT_POSIX
-
-#if MICROPY_PY_SELECT
-#error "Can't have both MICROPY_PY_SELECT and MICROPY_PY_SELECT_POSIX."
-#endif
-
-#include <stdio.h>
-#include <errno.h>
-#include <poll.h>
-
-#include "py/runtime.h"
-#include "py/stream.h"
-#include "py/obj.h"
-#include "py/objlist.h"
-#include "py/objtuple.h"
-#include "py/mphal.h"
-#include "py/mpthread.h"
-
-#define DEBUG 0
-
-#if MICROPY_PY_SOCKET
-extern const mp_obj_type_t mp_type_socket;
-#endif
-
-// Flags for poll()
-#define FLAG_ONESHOT (1)
-
-/// \class Poll - poll class
-
-typedef struct _mp_obj_poll_t {
-    mp_obj_base_t base;
-    unsigned short alloc;
-    unsigned short len;
-    struct pollfd *entries;
-    mp_obj_t *obj_map;
-    short iter_cnt;
-    short iter_idx;
-    int flags;
-    // callee-owned tuple
-    mp_obj_t ret_tuple;
-} mp_obj_poll_t;
-
-STATIC int get_fd(mp_obj_t fdlike) {
-    if (mp_obj_is_obj(fdlike)) {
-        const mp_stream_p_t *stream_p = mp_get_stream_raise(fdlike, MP_STREAM_OP_IOCTL);
-        int err;
-        mp_uint_t res = stream_p->ioctl(fdlike, MP_STREAM_GET_FILENO, 0, &err);
-        if (res != MP_STREAM_ERROR) {
-            return res;
-        }
-    }
-    return mp_obj_get_int(fdlike);
-}
-
-/// \method register(obj[, eventmask])
-STATIC mp_obj_t poll_register(size_t n_args, const mp_obj_t *args) {
-    mp_obj_poll_t *self = MP_OBJ_TO_PTR(args[0]);
-    bool is_fd = mp_obj_is_int(args[1]);
-    int fd = get_fd(args[1]);
-
-    mp_uint_t flags;
-    if (n_args == 3) {
-        flags = mp_obj_get_int(args[2]);
-    } else {
-        flags = POLLIN | POLLOUT;
-    }
-
-    struct pollfd *free_slot = NULL;
-
-    struct pollfd *entry = self->entries;
-    for (int i = 0; i < self->len; i++, entry++) {
-        int entry_fd = entry->fd;
-        if (entry_fd == fd) {
-            entry->events = flags;
-            return mp_const_false;
-        }
-        if (entry_fd == -1) {
-            free_slot = entry;
-        }
-    }
-
-    if (free_slot == NULL) {
-        if (self->len >= self->alloc) {
-            self->entries = m_renew(struct pollfd, self->entries, self->alloc, self->alloc + 4);
-            if (self->obj_map) {
-                self->obj_map = m_renew(mp_obj_t, self->obj_map, self->alloc, self->alloc + 4);
-            }
-            self->alloc += 4;
-        }
-        free_slot = &self->entries[self->len++];
-    }
-
-    if (!is_fd) {
-        if (self->obj_map == NULL) {
-            self->obj_map = m_new0(mp_obj_t, self->alloc);
-        }
-        self->obj_map[free_slot - self->entries] = args[1];
-    }
-
-    free_slot->fd = fd;
-    free_slot->events = flags;
-    free_slot->revents = 0;
-    return mp_const_true;
-}
-MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(poll_register_obj, 2, 3, poll_register);
-
-/// \method unregister(obj)
-STATIC mp_obj_t poll_unregister(mp_obj_t self_in, mp_obj_t obj_in) {
-    mp_obj_poll_t *self = MP_OBJ_TO_PTR(self_in);
-    struct pollfd *entries = self->entries;
-    int fd = get_fd(obj_in);
-    for (int i = self->len - 1; i >= 0; i--) {
-        if (entries->fd == fd) {
-            entries->fd = -1;
-            if (self->obj_map) {
-                self->obj_map[entries - self->entries] = MP_OBJ_NULL;
-            }
-            break;
-        }
-        entries++;
-    }
-
-    // TODO raise KeyError if obj didn't exist in map
-    return mp_const_none;
-}
-MP_DEFINE_CONST_FUN_OBJ_2(poll_unregister_obj, poll_unregister);
-
-/// \method modify(obj, eventmask)
-STATIC mp_obj_t poll_modify(mp_obj_t self_in, mp_obj_t obj_in, mp_obj_t eventmask_in) {
-    mp_obj_poll_t *self = MP_OBJ_TO_PTR(self_in);
-    struct pollfd *entries = self->entries;
-    int fd = get_fd(obj_in);
-    for (int i = self->len - 1; i >= 0; i--) {
-        if (entries->fd == fd) {
-            entries->events = mp_obj_get_int(eventmask_in);
-            return mp_const_none;
-        }
-        entries++;
-    }
-
-    // obj doesn't exist in poller
-    mp_raise_OSError(MP_ENOENT);
-}
-MP_DEFINE_CONST_FUN_OBJ_3(poll_modify_obj, poll_modify);
-
-STATIC int poll_poll_internal(size_t n_args, const mp_obj_t *args) {
-    mp_obj_poll_t *self = MP_OBJ_TO_PTR(args[0]);
-
-    // work out timeout (it's given already in ms)
-    int timeout = -1;
-    int flags = 0;
-    if (n_args >= 2) {
-        if (args[1] != mp_const_none) {
-            mp_int_t timeout_i = mp_obj_get_int(args[1]);
-            if (timeout_i >= 0) {
-                timeout = timeout_i;
-            }
-        }
-        if (n_args >= 3) {
-            flags = mp_obj_get_int(args[2]);
-        }
-    }
-
-    self->flags = flags;
-
-    int n_ready;
-    MP_HAL_RETRY_SYSCALL(n_ready, poll(self->entries, self->len, timeout), mp_raise_OSError(err));
-    return n_ready;
-}
-
-/// \method poll([timeout])
-/// Timeout is in milliseconds.
-STATIC mp_obj_t poll_poll(size_t n_args, const mp_obj_t *args) {
-    int n_ready = poll_poll_internal(n_args, args);
-
-    if (n_ready == 0) {
-        return mp_const_empty_tuple;
-    }
-
-    mp_obj_poll_t *self = MP_OBJ_TO_PTR(args[0]);
-
-    mp_obj_list_t *ret_list = MP_OBJ_TO_PTR(mp_obj_new_list(n_ready, NULL));
-    int ret_i = 0;
-    struct pollfd *entries = self->entries;
-    for (int i = 0; i < self->len; i++, entries++) {
-        if (entries->revents != 0) {
-            mp_obj_tuple_t *t = MP_OBJ_TO_PTR(mp_obj_new_tuple(2, NULL));
-            // If there's an object stored, return it, otherwise raw fd
-            if (self->obj_map && self->obj_map[i] != MP_OBJ_NULL) {
-                t->items[0] = self->obj_map[i];
-            } else {
-                t->items[0] = MP_OBJ_NEW_SMALL_INT(entries->fd);
-            }
-            t->items[1] = MP_OBJ_NEW_SMALL_INT(entries->revents);
-            ret_list->items[ret_i++] = MP_OBJ_FROM_PTR(t);
-            if (self->flags & FLAG_ONESHOT) {
-                entries->events = 0;
-            }
-        }
-    }
-
-    return MP_OBJ_FROM_PTR(ret_list);
-}
-MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(poll_poll_obj, 1, 3, poll_poll);
-
-STATIC mp_obj_t poll_ipoll(size_t n_args, const mp_obj_t *args) {
-    mp_obj_poll_t *self = MP_OBJ_TO_PTR(args[0]);
-
-    if (self->ret_tuple == MP_OBJ_NULL) {
-        self->ret_tuple = mp_obj_new_tuple(2, NULL);
-    }
-
-    int n_ready = poll_poll_internal(n_args, args);
-    self->iter_cnt = n_ready;
-    self->iter_idx = 0;
-
-    return args[0];
-}
-MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(poll_ipoll_obj, 1, 3, poll_ipoll);
-
-STATIC mp_obj_t poll_iternext(mp_obj_t self_in) {
-    mp_obj_poll_t *self = MP_OBJ_TO_PTR(self_in);
-
-    if (self->iter_cnt == 0) {
-        return MP_OBJ_STOP_ITERATION;
-    }
-
-    self->iter_cnt--;
-
-    struct pollfd *entries = self->entries + self->iter_idx;
-    for (int i = self->iter_idx; i < self->len; i++, entries++) {
-        self->iter_idx++;
-        if (entries->revents != 0) {
-            mp_obj_tuple_t *t = MP_OBJ_TO_PTR(self->ret_tuple);
-            // If there's an object stored, return it, otherwise raw fd
-            if (self->obj_map && self->obj_map[i] != MP_OBJ_NULL) {
-                t->items[0] = self->obj_map[i];
-            } else {
-                t->items[0] = MP_OBJ_NEW_SMALL_INT(entries->fd);
-            }
-            t->items[1] = MP_OBJ_NEW_SMALL_INT(entries->revents);
-            if (self->flags & FLAG_ONESHOT) {
-                entries->events = 0;
-            }
-            return MP_OBJ_FROM_PTR(t);
-        }
-    }
-
-    assert(!"inconsistent number of poll active entries");
-    self->iter_cnt = 0;
-    return MP_OBJ_STOP_ITERATION;
-}
-
-#if DEBUG
-STATIC mp_obj_t poll_dump(mp_obj_t self_in) {
-    mp_obj_poll_t *self = MP_OBJ_TO_PTR(self_in);
-
-    struct pollfd *entries = self->entries;
-    for (int i = self->len - 1; i >= 0; i--) {
-        printf("fd: %d ev: %x rev: %x", entries->fd, entries->events, entries->revents);
-        if (self->obj_map) {
-            printf(" obj: %p", self->obj_map[entries - self->entries]);
-        }
-        printf("\n");
-        entries++;
-    }
-
-    return mp_const_none;
-}
-MP_DEFINE_CONST_FUN_OBJ_1(poll_dump_obj, poll_dump);
-#endif
-
-STATIC const mp_rom_map_elem_t poll_locals_dict_table[] = {
-    { MP_ROM_QSTR(MP_QSTR_register), MP_ROM_PTR(&poll_register_obj) },
-    { MP_ROM_QSTR(MP_QSTR_unregister), MP_ROM_PTR(&poll_unregister_obj) },
-    { MP_ROM_QSTR(MP_QSTR_modify), MP_ROM_PTR(&poll_modify_obj) },
-    { MP_ROM_QSTR(MP_QSTR_poll), MP_ROM_PTR(&poll_poll_obj) },
-    { MP_ROM_QSTR(MP_QSTR_ipoll), MP_ROM_PTR(&poll_ipoll_obj) },
-    #if DEBUG
-    { MP_ROM_QSTR(MP_QSTR_dump), MP_ROM_PTR(&poll_dump_obj) },
-    #endif
-};
-STATIC MP_DEFINE_CONST_DICT(poll_locals_dict, poll_locals_dict_table);
-
-STATIC MP_DEFINE_CONST_OBJ_TYPE(
-    mp_type_poll,
-    MP_QSTR_poll,
-    MP_TYPE_FLAG_ITER_IS_ITERNEXT,
-    iter, poll_iternext,
-    locals_dict, &poll_locals_dict
-    );
-
-STATIC mp_obj_t select_poll(size_t n_args, const mp_obj_t *args) {
-    int alloc = 4;
-    if (n_args > 0) {
-        alloc = mp_obj_get_int(args[0]);
-    }
-    mp_obj_poll_t *poll = mp_obj_malloc(mp_obj_poll_t, &mp_type_poll);
-    poll->entries = m_new(struct pollfd, alloc);
-    poll->alloc = alloc;
-    poll->len = 0;
-    poll->obj_map = NULL;
-    poll->iter_cnt = 0;
-    poll->ret_tuple = MP_OBJ_NULL;
-    return MP_OBJ_FROM_PTR(poll);
-}
-MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(mp_select_poll_obj, 0, 1, select_poll);
-
-STATIC const mp_rom_map_elem_t mp_module_select_globals_table[] = {
-    { MP_ROM_QSTR(MP_QSTR___name__), MP_ROM_QSTR(MP_QSTR_select) },
-    { MP_ROM_QSTR(MP_QSTR_poll), MP_ROM_PTR(&mp_select_poll_obj) },
-    { MP_ROM_QSTR(MP_QSTR_POLLIN), MP_ROM_INT(POLLIN) },
-    { MP_ROM_QSTR(MP_QSTR_POLLOUT), MP_ROM_INT(POLLOUT) },
-    { MP_ROM_QSTR(MP_QSTR_POLLERR), MP_ROM_INT(POLLERR) },
-    { MP_ROM_QSTR(MP_QSTR_POLLHUP), MP_ROM_INT(POLLHUP) },
-};
-
-STATIC MP_DEFINE_CONST_DICT(mp_module_select_globals, mp_module_select_globals_table);
-
-const mp_obj_module_t mp_module_select = {
-    .base = { &mp_type_module },
-    .globals = (mp_obj_dict_t *)&mp_module_select_globals,
-};
-
-MP_REGISTER_EXTENSIBLE_MODULE(MP_QSTR_select, mp_module_select);
-
-#endif // MICROPY_PY_SELECT_POSIX
diff --git a/ports/unix/modsocket.c b/ports/unix/modsocket.c
index 871be8dcf7..737550b428 100644
--- a/ports/unix/modsocket.c
+++ b/ports/unix/modsocket.c
@@ -164,6 +164,15 @@ STATIC mp_uint_t socket_ioctl(mp_obj_t o_in, mp_uint_t request, uintptr_t arg, i
                 if (pfd.revents & POLLOUT) {
                     ret |= MP_STREAM_POLL_WR;
                 }
+                if (pfd.revents & POLLERR) {
+                    ret |= MP_STREAM_POLL_ERR;
+                }
+                if (pfd.revents & POLLHUP) {
+                    ret |= MP_STREAM_POLL_HUP;
+                }
+                if (pfd.revents & POLLNVAL) {
+                    ret |= MP_STREAM_POLL_NVAL;
+                }
             }
             return ret;
         }
diff --git a/ports/unix/mpconfigport.h b/ports/unix/mpconfigport.h
index c20aff1683..2de05a0a6c 100644
--- a/ports/unix/mpconfigport.h
+++ b/ports/unix/mpconfigport.h
@@ -134,12 +134,6 @@ typedef long mp_off_t;
 #define MICROPY_STACKLESS_STRICT    (0)
 #endif
 
-// If settrace is enabled then we need code saving.
-#if MICROPY_PY_SYS_SETTRACE
-#define MICROPY_PERSISTENT_CODE_SAVE (1)
-#define MICROPY_COMP_CONST (0)
-#endif
-
 // Unix-specific configuration of machine.mem*.
 #define MICROPY_MACHINE_MEM_GET_READ_ADDR   mod_machine_mem_get_addr
 #define MICROPY_MACHINE_MEM_GET_WRITE_ADDR  mod_machine_mem_get_addr
diff --git a/ports/unix/mpthreadport.c b/ports/unix/mpthreadport.c
index 6a267e7236..2190bf4ad1 100644
--- a/ports/unix/mpthreadport.c
+++ b/ports/unix/mpthreadport.c
@@ -191,6 +191,10 @@ void mp_thread_set_state(mp_state_thread_t *state) {
     pthread_setspecific(tls_key, state);
 }
 
+mp_uint_t mp_thread_get_id(void) {
+    return (mp_uint_t)pthread_self();
+}
+
 void mp_thread_start(void) {
     // enable realtime priority if `-X realtime` command line parameter was set
     #if defined(__APPLE__)
@@ -210,7 +214,7 @@ void mp_thread_start(void) {
     mp_thread_unix_end_atomic_section();
 }
 
-void mp_thread_create(void *(*entry)(void *), void *arg, size_t *stack_size) {
+mp_uint_t mp_thread_create(void *(*entry)(void *), void *arg, size_t *stack_size) {
     // default stack size is 8k machine-words
     if (*stack_size == 0) {
         *stack_size = 8192 * sizeof(void *);
@@ -265,7 +269,8 @@ void mp_thread_create(void *(*entry)(void *), void *arg, size_t *stack_size) {
 
     mp_thread_unix_end_atomic_section();
 
-    return;
+    MP_STATIC_ASSERT(sizeof(mp_uint_t) >= sizeof(pthread_t));
+    return (mp_uint_t)id;
 
 er:
     mp_raise_OSError(ret);
diff --git a/ports/unix/variants/mpconfigvariant_common.h b/ports/unix/variants/mpconfigvariant_common.h
index 8cb1f88e68..082938ed5f 100644
--- a/ports/unix/variants/mpconfigvariant_common.h
+++ b/ports/unix/variants/mpconfigvariant_common.h
@@ -106,14 +106,9 @@
 #define MICROPY_PY_CRYPTOLIB           (1)
 #endif
 
-// Use the posix implementation of the "select" module (unless the variant
-// specifically asks for the MicroPython version).
-#ifndef MICROPY_PY_SELECT
-#define MICROPY_PY_SELECT              (0)
-#endif
-#ifndef MICROPY_PY_SELECT_POSIX
-#define MICROPY_PY_SELECT_POSIX        (!MICROPY_PY_SELECT)
-#endif
+// The "select" module is enabled by default, but disable select.select().
+#define MICROPY_PY_SELECT_POSIX_OPTIMISATIONS (1)
+#define MICROPY_PY_SELECT_SELECT       (0)
 
 // Enable the "websocket" module.
 #define MICROPY_PY_WEBSOCKET           (1)
diff --git a/py/dynruntime.h b/py/dynruntime.h
index 8564715c0b..90c401ab4b 100644
--- a/py/dynruntime.h
+++ b/py/dynruntime.h
@@ -79,7 +79,7 @@ static inline void *m_realloc_dyn(void *ptr, size_t new_num_bytes) {
 /******************************************************************************/
 // Types and objects
 
-#define MP_OBJ_NEW_QSTR(x) MP_OBJ_NEW_QSTR_##x
+#define MP_OBJ_NEW_QSTR(x)                  (mp_fun_table.native_to_obj(x, MP_NATIVE_TYPE_QSTR))
 
 #define mp_type_type                        (*mp_fun_table.type_type)
 #define mp_type_NoneType                    (*mp_obj_get_type(mp_const_none))
diff --git a/py/gc.c b/py/gc.c
index 9fefd3638b..b2e4aa4aae 100644
--- a/py/gc.c
+++ b/py/gc.c
@@ -79,7 +79,7 @@
 #define ATB_3_IS_FREE(a) (((a) & ATB_MASK_3) == 0)
 
 #if MICROPY_GC_SPLIT_HEAP
-#define NEXT_AREA(area) (area->next)
+#define NEXT_AREA(area) ((area)->next)
 #else
 #define NEXT_AREA(area) (NULL)
 #endif
@@ -129,7 +129,13 @@ STATIC void gc_setup_area(mp_state_mem_area_t *area, void *start, void *end) {
     // => T = A * (1 + BLOCKS_PER_ATB / BLOCKS_PER_FTB + BLOCKS_PER_ATB * BYTES_PER_BLOCK)
     size_t total_byte_len = (byte *)end - (byte *)start;
     #if MICROPY_ENABLE_FINALISER
-    area->gc_alloc_table_byte_len = (total_byte_len - ALLOC_TABLE_GAP_BYTE) * MP_BITS_PER_BYTE / (MP_BITS_PER_BYTE + MP_BITS_PER_BYTE * BLOCKS_PER_ATB / BLOCKS_PER_FTB + MP_BITS_PER_BYTE * BLOCKS_PER_ATB * BYTES_PER_BLOCK);
+    area->gc_alloc_table_byte_len = (total_byte_len - ALLOC_TABLE_GAP_BYTE)
+        * MP_BITS_PER_BYTE
+        / (
+            MP_BITS_PER_BYTE
+            + MP_BITS_PER_BYTE * BLOCKS_PER_ATB / BLOCKS_PER_FTB
+            + MP_BITS_PER_BYTE * BLOCKS_PER_ATB * BYTES_PER_BLOCK
+            );
     #else
     area->gc_alloc_table_byte_len = (total_byte_len - ALLOC_TABLE_GAP_BYTE) / (1 + MP_BITS_PER_BYTE / 2 * BYTES_PER_BLOCK);
     #endif
@@ -158,17 +164,26 @@ STATIC void gc_setup_area(mp_state_mem_area_t *area, void *start, void *end) {
     #endif
 
     area->gc_last_free_atb_index = 0;
+    area->gc_last_used_block = 0;
 
     #if MICROPY_GC_SPLIT_HEAP
     area->next = NULL;
     #endif
 
     DEBUG_printf("GC layout:\n");
-    DEBUG_printf("  alloc table at %p, length " UINT_FMT " bytes, " UINT_FMT " blocks\n", MP_STATE_MEM(area).gc_alloc_table_start, MP_STATE_MEM(area).gc_alloc_table_byte_len, MP_STATE_MEM(area).gc_alloc_table_byte_len * BLOCKS_PER_ATB);
+    DEBUG_printf("  alloc table at %p, length " UINT_FMT " bytes, "
+        UINT_FMT " blocks\n",
+        area->gc_alloc_table_start, area->gc_alloc_table_byte_len,
+        area->gc_alloc_table_byte_len * BLOCKS_PER_ATB);
     #if MICROPY_ENABLE_FINALISER
-    DEBUG_printf("  finaliser table at %p, length " UINT_FMT " bytes, " UINT_FMT " blocks\n", MP_STATE_MEM(area).gc_finaliser_table_start, gc_finaliser_table_byte_len, gc_finaliser_table_byte_len * BLOCKS_PER_FTB);
+    DEBUG_printf("  finaliser table at %p, length " UINT_FMT " bytes, "
+        UINT_FMT " blocks\n", area->gc_finaliser_table_start,
+        gc_finaliser_table_byte_len,
+        gc_finaliser_table_byte_len * BLOCKS_PER_FTB);
     #endif
-    DEBUG_printf("  pool at %p, length " UINT_FMT " bytes, " UINT_FMT " blocks\n", MP_STATE_MEM(area).gc_pool_start, gc_pool_block_len * BYTES_PER_BLOCK, gc_pool_block_len);
+    DEBUG_printf("  pool at %p, length " UINT_FMT " bytes, "
+        UINT_FMT " blocks\n", area->gc_pool_start,
+        gc_pool_block_len * BYTES_PER_BLOCK, gc_pool_block_len);
 }
 
 void gc_init(void *start, void *end) {
@@ -221,6 +236,83 @@ void gc_add(void *start, void *end) {
     // Add this area to the linked list
     prev_area->next = area;
 }
+
+#if MICROPY_GC_SPLIT_HEAP_AUTO
+// Try to automatically add a heap area large enough to fulfill 'failed_alloc'.
+STATIC bool gc_try_add_heap(size_t failed_alloc) {
+    // 'needed' is the size of a heap large enough to hold failed_alloc, with
+    // the additional metadata overheads as calculated in gc_setup_area().
+    //
+    // Rather than reproduce all of that logic here, we approximate that adding
+    // (13/512) is enough overhead for sufficiently large heap areas (the
+    // overhead converges to 3/128, but there's some fixed overhead and some
+    // rounding up of partial block sizes).
+    size_t needed = failed_alloc + MAX(2048, failed_alloc * 13 / 512);
+
+    size_t avail = gc_get_max_new_split();
+
+    DEBUG_printf("gc_try_add_heap failed_alloc " UINT_FMT ", "
+        "needed " UINT_FMT ", avail " UINT_FMT " bytes \n",
+        failed_alloc,
+        needed,
+        avail);
+
+    if (avail < needed) {
+        // Can't fit this allocation, or system heap has nearly run out anyway
+        return false;
+    }
+
+    // Deciding how much to grow the total heap by each time is tricky:
+    //
+    // - Grow by too small amounts, leads to heap fragmentation issues.
+    //
+    // - Grow by too large amounts, may lead to system heap running out of
+    //   space.
+    //
+    // Currently, this implementation is:
+    //
+    // - At minimum, aim to double the total heap size each time we add a new
+    //   heap.  i.e. without any large single allocations, total size will be
+    //   64KB -> 128KB -> 256KB -> 512KB -> 1MB, etc
+    //
+    // - If the failed allocation is too large to fit in that size, the new
+    //   heap is made exactly large enough for that allocation. Future growth
+    //   will double the total heap size again.
+    //
+    // - If the new heap won't fit in the available free space, add the largest
+    //   new heap that will fit (this may lead to failed system heap allocations
+    //   elsewhere, but some allocation will likely fail in this circumstance!)
+    size_t total_heap = 0;
+    for (mp_state_mem_area_t *area = &MP_STATE_MEM(area);
+         area != NULL;
+         area = NEXT_AREA(area)) {
+        total_heap += area->gc_pool_end - area->gc_alloc_table_start;
+        total_heap += ALLOC_TABLE_GAP_BYTE + sizeof(mp_state_mem_area_t);
+    }
+
+    DEBUG_printf("total_heap " UINT_FMT " bytes\n", total_heap);
+
+    size_t to_alloc = MIN(avail, MAX(total_heap, needed));
+
+    mp_state_mem_area_t *new_heap = MP_PLAT_ALLOC_HEAP(to_alloc);
+
+    DEBUG_printf("MP_PLAT_ALLOC_HEAP " UINT_FMT " = %p\n",
+        to_alloc, new_heap);
+
+    if (new_heap == NULL) {
+        // This should only fail:
+        // - In a threaded environment if another thread has
+        //   allocated while this function ran.
+        // - If there is a bug in gc_get_max_new_split().
+        return false;
+    }
+
+    gc_add(new_heap, (void *)new_heap + to_alloc);
+
+    return true;
+}
+#endif
+
 #endif
 
 void gc_lock(void) {
@@ -377,8 +469,18 @@ STATIC void gc_sweep(void) {
     #endif
     // free unmarked heads and their tails
     int free_tail = 0;
+    #if MICROPY_GC_SPLIT_HEAP_AUTO
+    mp_state_mem_area_t *prev_area = NULL;
+    #endif
     for (mp_state_mem_area_t *area = &MP_STATE_MEM(area); area != NULL; area = NEXT_AREA(area)) {
-        for (size_t block = 0; block < area->gc_alloc_table_byte_len * BLOCKS_PER_ATB; block++) {
+        size_t end_block = area->gc_alloc_table_byte_len * BLOCKS_PER_ATB;
+        if (area->gc_last_used_block < end_block) {
+            end_block = area->gc_last_used_block + 1;
+        }
+
+        size_t last_used_block = 0;
+
+        for (size_t block = 0; block < end_block; block++) {
             MICROPY_GC_HOOK_LOOP(block);
             switch (ATB_GET_KIND(area, block)) {
                 case AT_HEAD:
@@ -418,15 +520,31 @@ STATIC void gc_sweep(void) {
                         #if CLEAR_ON_SWEEP
                         memset((void *)PTR_FROM_BLOCK(area, block), 0, BYTES_PER_BLOCK);
                         #endif
+                    } else {
+                        last_used_block = block;
                     }
                     break;
 
                 case AT_MARK:
                     ATB_MARK_TO_HEAD(area, block);
                     free_tail = 0;
+                    last_used_block = block;
                     break;
             }
         }
+
+        area->gc_last_used_block = last_used_block;
+
+        #if MICROPY_GC_SPLIT_HEAP_AUTO
+        // Free any empty area, aside from the first one
+        if (last_used_block == 0 && prev_area != NULL) {
+            DEBUG_printf("gc_sweep free empty area %p\n", area);
+            NEXT_AREA(prev_area) = NEXT_AREA(area);
+            MP_PLAT_FREE_HEAP(area);
+            area = prev_area;
+        }
+        prev_area = area;
+        #endif
     }
 }
 
@@ -609,6 +727,9 @@ void *gc_alloc(size_t n_bytes, unsigned int alloc_flags) {
     size_t start_block;
     size_t n_free;
     int collected = !MP_STATE_MEM(gc_auto_collect_enabled);
+    #if MICROPY_GC_SPLIT_HEAP_AUTO
+    bool added = false;
+    #endif
 
     #if MICROPY_GC_ALLOC_THRESHOLD
     if (!collected && MP_STATE_MEM(gc_alloc_amount) >= MP_STATE_MEM(gc_alloc_threshold)) {
@@ -654,6 +775,12 @@ void *gc_alloc(size_t n_bytes, unsigned int alloc_flags) {
         GC_EXIT();
         // nothing found!
         if (collected) {
+            #if MICROPY_GC_SPLIT_HEAP_AUTO
+            if (!added && gc_try_add_heap(n_bytes)) {
+                added = true;
+                continue;
+            }
+            #endif
             return NULL;
         }
         DEBUG_printf("gc_alloc(" UINT_FMT "): no free mem, triggering GC\n", n_bytes);
@@ -680,6 +807,8 @@ found:
         area->gc_last_free_atb_index = (i + 1) / BLOCKS_PER_ATB;
     }
 
+    area->gc_last_used_block = MAX(area->gc_last_used_block, end_block);
+
     // mark first block as used head
     ATB_FREE_TO_HEAD(area, start_block);
 
@@ -971,11 +1100,14 @@ void *gc_realloc(void *ptr_in, size_t n_bytes, bool allow_move) {
     // check if we can expand in place
     if (new_blocks <= n_blocks + n_free) {
         // mark few more blocks as used tail
-        for (size_t bl = block + n_blocks; bl < block + new_blocks; bl++) {
+        size_t end_block = block + new_blocks;
+        for (size_t bl = block + n_blocks; bl < end_block; bl++) {
             assert(ATB_GET_KIND(area, bl) == AT_FREE);
             ATB_FREE_TO_TAIL(area, bl);
         }
 
+        area->gc_last_used_block = MAX(area->gc_last_used_block, end_block);
+
         GC_EXIT();
 
         #if MICROPY_GC_CONSERVATIVE_CLEAR
@@ -1024,9 +1156,12 @@ void *gc_realloc(void *ptr_in, size_t n_bytes, bool allow_move) {
 void gc_dump_info(const mp_print_t *print) {
     gc_info_t info;
     gc_info(&info);
-    mp_printf(print, "GC: total: %u, used: %u, free: %u\n",
+    mp_printf(print, "GC: total: %u, used: %u, free: %u",
         (uint)info.total, (uint)info.used, (uint)info.free);
-    mp_printf(print, " No. of 1-blocks: %u, 2-blocks: %u, max blk sz: %u, max free sz: %u\n",
+    #if MICROPY_GC_SPLIT_HEAP_AUTO
+    mp_printf(print, ", max new split: %u", (uint)gc_get_max_new_split());
+    #endif
+    mp_printf(print, "\n No. of 1-blocks: %u, 2-blocks: %u, max blk sz: %u, max free sz: %u\n",
         (uint)info.num_1block, (uint)info.num_2block, (uint)info.max_block, (uint)info.max_free);
 }
 
diff --git a/py/gc.h b/py/gc.h
index 8431c0a6cf..7eec6265c8 100644
--- a/py/gc.h
+++ b/py/gc.h
@@ -35,7 +35,13 @@ void gc_init(void *start, void *end);
 #if MICROPY_GC_SPLIT_HEAP
 // Used to add additional memory areas to the heap.
 void gc_add(void *start, void *end);
-#endif
+
+#if MICROPY_GC_SPLIT_HEAP_AUTO
+// Port must implement this function to return the maximum available block of
+// RAM to allocate a new heap area into using MP_PLAT_ALLOC_HEAP.
+size_t gc_get_max_new_split(void);
+#endif // MICROPY_GC_SPLIT_HEAP_AUTO
+#endif // MICROPY_GC_SPLIT_HEAP
 
 // These lock/unlock functions can be nested.
 // They can be used to prevent the GC from allocating/freeing.
diff --git a/py/malloc.c b/py/malloc.c
index efdff75396..ddf139e386 100644
--- a/py/malloc.c
+++ b/py/malloc.c
@@ -185,7 +185,7 @@ void *m_realloc_maybe(void *ptr, size_t new_num_bytes, bool allow_move)
     #if MICROPY_MALLOC_USES_ALLOCATED_SIZE
     DEBUG_printf("realloc %p, %d, %d : %p\n", ptr, old_num_bytes, new_num_bytes, new_ptr);
     #else
-    DEBUG_printf("realloc %p, %d, %d : %p\n", ptr, new_num_bytes, new_ptr);
+    DEBUG_printf("realloc %p, %d : %p\n", ptr, new_num_bytes, new_ptr);
     #endif
     return new_ptr;
 }
diff --git a/py/mkenv.mk b/py/mkenv.mk
index 5368279e29..d3dddcc32d 100644
--- a/py/mkenv.mk
+++ b/py/mkenv.mk
@@ -42,6 +42,7 @@ SED = sed
 CAT = cat
 TOUCH = touch
 PYTHON = python3
+ZIP = zip
 
 AS = $(CROSS_COMPILE)as
 CC = $(CROSS_COMPILE)gcc
diff --git a/py/mkrules.cmake b/py/mkrules.cmake
index 7eb5fcf018..02e3148f2b 100644
--- a/py/mkrules.cmake
+++ b/py/mkrules.cmake
@@ -178,7 +178,12 @@ if(MICROPY_FROZEN_MANIFEST)
         set(MICROPY_LIB_DIR ${MICROPY_DIR}/lib/micropython-lib)
     endif()
 
-    if(NOT (${ECHO_SUBMODULES}) AND NOT EXISTS ${MICROPY_LIB_DIR}/README.md)
+    if(ECHO_SUBMODULES)
+        # No-op, we're just doing submodule/variant discovery.
+        # Note: All the following rules are safe to run in discovery mode even
+        # though the submodule might not be available as they do not directly depend
+        # on anything from the submodule.
+    elseif(NOT EXISTS ${MICROPY_LIB_DIR}/README.md)
         message(FATAL_ERROR " micropython-lib not initialized.\n Run 'make BOARD=${MICROPY_BOARD} submodules'")
     endif()
 
@@ -218,9 +223,3 @@ if(ECHO_SUBMODULES)
     execute_process(COMMAND ${CMAKE_COMMAND} -E echo "GIT_SUBMODULES=${GIT_SUBMODULES}")
     message(FATAL_ERROR "Done")
 endif()
-
-# Display BOARD_VARIANTS
-if(ECHO_BOARD_VARIANTS)
-    execute_process(COMMAND ${CMAKE_COMMAND} -E echo "BOARD_VARIANTS=${BOARD_VARIANTS}")
-    message(FATAL_ERROR "Done")
-endif()
diff --git a/py/modstruct.c b/py/modstruct.c
index 42f91b282c..b3edc96328 100644
--- a/py/modstruct.c
+++ b/py/modstruct.c
@@ -92,7 +92,9 @@ STATIC size_t calc_size_items(const char *fmt, size_t *total_sz) {
             cnt = get_fmt_num(&fmt);
         }
 
-        if (*fmt == 's') {
+        if (*fmt == 'x') {
+            size += cnt;
+        } else if (*fmt == 's') {
             total_cnt += 1;
             size += cnt;
         } else {
@@ -159,7 +161,9 @@ STATIC mp_obj_t struct_unpack_from(size_t n_args, const mp_obj_t *args) {
             cnt = get_fmt_num(&fmt);
         }
         mp_obj_t item;
-        if (*fmt == 's') {
+        if (*fmt == 'x') {
+            p += cnt;
+        } else if (*fmt == 's') {
             item = mp_obj_new_bytes(p, cnt);
             p += cnt;
             res->items[i++] = item;
@@ -192,7 +196,10 @@ STATIC void struct_pack_into_internal(mp_obj_t fmt_in, byte *p, size_t n_args, c
             cnt = get_fmt_num(&fmt);
         }
 
-        if (*fmt == 's') {
+        if (*fmt == 'x') {
+            memset(p, 0, cnt);
+            p += cnt;
+        } else if (*fmt == 's') {
             mp_buffer_info_t bufinfo;
             mp_get_buffer_raise(args[i++], &bufinfo, MP_BUFFER_READ);
             mp_uint_t to_copy = cnt;
diff --git a/py/modthread.c b/py/modthread.c
index 51d63e4703..6b75474904 100644
--- a/py/modthread.c
+++ b/py/modthread.c
@@ -129,7 +129,7 @@ STATIC MP_DEFINE_CONST_OBJ_TYPE(
 STATIC size_t thread_stack_size = 0;
 
 STATIC mp_obj_t mod_thread_get_ident(void) {
-    return mp_obj_new_int_from_uint((uintptr_t)mp_thread_get_state());
+    return mp_obj_new_int_from_uint(mp_thread_get_id());
 }
 STATIC MP_DEFINE_CONST_FUN_OBJ_0(mod_thread_get_ident_obj, mod_thread_get_ident);
 
@@ -268,9 +268,7 @@ STATIC mp_obj_t mod_thread_start_new_thread(size_t n_args, const mp_obj_t *args)
     th_args->fun = args[0];
 
     // spawn the thread!
-    mp_thread_create(thread_entry, th_args, &th_args->stack_size);
-
-    return mp_const_none;
+    return mp_obj_new_int_from_uint(mp_thread_create(thread_entry, th_args, &th_args->stack_size));
 }
 STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(mod_thread_start_new_thread_obj, 2, 3, mod_thread_start_new_thread);
 
diff --git a/py/mpconfig.h b/py/mpconfig.h
index c617f573b6..433d6e50de 100644
--- a/py/mpconfig.h
+++ b/py/mpconfig.h
@@ -312,9 +312,11 @@
 #define MICROPY_PERSISTENT_CODE_LOAD (0)
 #endif
 
-// Whether to support saving of persistent code
+// Whether to support saving of persistent code, i.e. for mpy-cross to
+// generate .mpy files. Enabling this enables additional metadata on raw code
+// objects which is also required for sys.settrace.
 #ifndef MICROPY_PERSISTENT_CODE_SAVE
-#define MICROPY_PERSISTENT_CODE_SAVE (0)
+#define MICROPY_PERSISTENT_CODE_SAVE (MICROPY_PY_SYS_SETTRACE)
 #endif
 
 // Whether to support saving persistent code to a file via mp_raw_code_save_file
@@ -616,6 +618,11 @@
 #define MICROPY_GC_SPLIT_HEAP (0)
 #endif
 
+// Whether regions should be added/removed from the split heap as needed.
+#ifndef MICROPY_GC_SPLIT_HEAP_AUTO
+#define MICROPY_GC_SPLIT_HEAP_AUTO (0)
+#endif
+
 // Hook to run code during time consuming garbage collector operations
 // *i* is the loop index variable (e.g. can be used to run every x loops)
 #ifndef MICROPY_GC_HOOK_LOOP
@@ -1485,11 +1492,16 @@ typedef double mp_float_t;
 #define MICROPY_PY_ERRNO_ERRORCODE (1)
 #endif
 
-// Whether to provide "select" module (baremetal implementation)
+// Whether to provide "select" module
 #ifndef MICROPY_PY_SELECT
 #define MICROPY_PY_SELECT (MICROPY_CONFIG_ROM_LEVEL_AT_LEAST_EXTRA_FEATURES)
 #endif
 
+// Whether to enable POSIX optimisations in the "select" module (requires system poll)
+#ifndef MICROPY_PY_SELECT_POSIX_OPTIMISATIONS
+#define MICROPY_PY_SELECT_POSIX_OPTIMISATIONS (0)
+#endif
+
 // Whether to enable the select() function in the "select" module (baremetal
 // implementation). This is present for compatibility but can be disabled to
 // save space.
@@ -1706,7 +1718,7 @@ typedef double mp_float_t;
 
 // Whether to add finaliser code to ssl objects
 #ifndef MICROPY_PY_SSL_FINALISER
-#define MICROPY_PY_SSL_FINALISER (0)
+#define MICROPY_PY_SSL_FINALISER (MICROPY_ENABLE_FINALISER)
 #endif
 
 #ifndef MICROPY_PY_WEBSOCKET
@@ -1891,6 +1903,16 @@ typedef double mp_float_t;
 #define MP_PLAT_FREE_EXEC(ptr, size) m_del(byte, ptr, size)
 #endif
 
+// Allocating new heap area at runtime requires port to be able to allocate from system heap
+#if MICROPY_GC_SPLIT_HEAP_AUTO
+#ifndef MP_PLAT_ALLOC_HEAP
+#define MP_PLAT_ALLOC_HEAP(size) malloc(size)
+#endif
+#ifndef MP_PLAT_FREE_HEAP
+#define MP_PLAT_FREE_HEAP(ptr) free(ptr)
+#endif
+#endif
+
 // This macro is used to do all output (except when MICROPY_PY_IO is defined)
 #ifndef MP_PLAT_PRINT_STRN
 #define MP_PLAT_PRINT_STRN(str, len) mp_hal_stdout_tx_strn_cooked(str, len)
@@ -1993,14 +2015,4 @@ typedef double mp_float_t;
 #define MP_WARN_CAT(x) (NULL)
 #endif
 
-// Feature dependency check.
-#if MICROPY_PY_SYS_SETTRACE
-#if !MICROPY_PERSISTENT_CODE_SAVE
-#error "MICROPY_PY_SYS_SETTRACE requires MICROPY_PERSISTENT_CODE_SAVE to be enabled"
-#endif
-#if MICROPY_COMP_CONST
-#error "MICROPY_PY_SYS_SETTRACE requires MICROPY_COMP_CONST to be disabled"
-#endif
-#endif
-
 #endif // MICROPY_INCLUDED_PY_MPCONFIG_H
diff --git a/py/mpstate.h b/py/mpstate.h
index 080dc1380b..64915ab87d 100644
--- a/py/mpstate.h
+++ b/py/mpstate.h
@@ -93,6 +93,7 @@ typedef struct _mp_state_mem_area_t {
     byte *gc_pool_end;
 
     size_t gc_last_free_atb_index;
+    size_t gc_last_used_block; // The block ID of the highest block allocated in the area
 } mp_state_mem_area_t;
 
 // This structure hold information about the memory allocation system.
diff --git a/py/mpthread.h b/py/mpthread.h
index e611ef4c11..f335cc0291 100644
--- a/py/mpthread.h
+++ b/py/mpthread.h
@@ -40,7 +40,8 @@ struct _mp_state_thread_t;
 
 struct _mp_state_thread_t *mp_thread_get_state(void);
 void mp_thread_set_state(struct _mp_state_thread_t *state);
-void mp_thread_create(void *(*entry)(void *), void *arg, size_t *stack_size);
+mp_uint_t mp_thread_create(void *(*entry)(void *), void *arg, size_t *stack_size);
+mp_uint_t mp_thread_get_id(void);
 void mp_thread_start(void);
 void mp_thread_finish(void);
 void mp_thread_mutex_init(mp_thread_mutex_t *mutex);
diff --git a/py/nativeglue.c b/py/nativeglue.c
index 743ff38ccb..d92d815abd 100644
--- a/py/nativeglue.c
+++ b/py/nativeglue.c
@@ -104,6 +104,8 @@ mp_obj_t mp_native_to_obj(mp_uint_t val, mp_uint_t type) {
             return mp_obj_new_int(val);
         case MP_NATIVE_TYPE_UINT:
             return mp_obj_new_int_from_uint(val);
+        case MP_NATIVE_TYPE_QSTR:
+            return MP_OBJ_NEW_QSTR(val);
         default: // a pointer
             // we return just the value of the pointer as an integer
             return mp_obj_new_int_from_uint(val);
diff --git a/py/objstr.c b/py/objstr.c
index b966a70169..5dfe94ac4f 100644
--- a/py/objstr.c
+++ b/py/objstr.c
@@ -1645,7 +1645,9 @@ STATIC mp_obj_t str_modulo_format(mp_obj_t pattern, size_t n_args, const mp_obj_
         }
     }
 
-    if (arg_i != n_args) {
+    if (dict == MP_OBJ_NULL && arg_i != n_args) {
+        // NOTE: if `dict` exists, then `n_args` is 1 and the dict is always consumed; either
+        // positionally, or as a map of named args, even if none were actually referenced.
         mp_raise_TypeError(MP_ERROR_TEXT("format string didn't convert all arguments"));
     }
 
diff --git a/py/profile.c b/py/profile.c
index 89af8640a0..274089d702 100644
--- a/py/profile.c
+++ b/py/profile.c
@@ -31,6 +31,12 @@
 
 #if MICROPY_PY_SYS_SETTRACE
 
+#if !MICROPY_PERSISTENT_CODE_SAVE
+// The settrace feature requires that we maintain additional metadata on the raw
+// code object which is normally only done when writing .mpy files.
+#error "MICROPY_PY_SYS_SETTRACE requires MICROPY_PERSISTENT_CODE_SAVE to be enabled"
+#endif
+
 #define prof_trace_cb MP_STATE_THREAD(prof_trace_callback)
 #define QSTR_MAP(context, idx) (context->constants.qstr_table[idx])
 
diff --git a/py/runtime0.h b/py/runtime0.h
index 6ef2d727c1..69af38ddcb 100644
--- a/py/runtime0.h
+++ b/py/runtime0.h
@@ -50,6 +50,9 @@
 #define MP_NATIVE_TYPE_PTR16 (0x06)
 #define MP_NATIVE_TYPE_PTR32 (0x07)
 
+// Not use for viper, but for dynamic native modules
+#define MP_NATIVE_TYPE_QSTR (0x08)
+
 // Bytecode and runtime boundaries for unary ops
 #define MP_UNARY_OP_NUM_BYTECODE    (MP_UNARY_OP_NOT + 1)
 #define MP_UNARY_OP_NUM_RUNTIME     (MP_UNARY_OP_SIZEOF + 1)
diff --git a/pyproject.toml b/pyproject.toml
index dfd26bd8c9..e3d70385c3 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -35,7 +35,6 @@ ignore = [
   "F401",
   "F403",
   "F405",
-  "F821",
   "PLC1901",
 ]
 line-length = 337
@@ -46,3 +45,7 @@ max-complexity = 40
 
 [tool.ruff.per-file-ignores]
 "ports/cc3200/tools/uniflash.py" = ["E711"]
+
+# manifest.py files are evaluated with some global names pre-defined
+"**/manifest.py" = ["F821"]
+"ports/**/boards/**/manifest_*.py" = ["F821"]
diff --git a/tests/basics/string_format_modulo.py b/tests/basics/string_format_modulo.py
index 14b4a6a484..7bddd96750 100644
--- a/tests/basics/string_format_modulo.py
+++ b/tests/basics/string_format_modulo.py
@@ -51,8 +51,9 @@ print('%c' % True)
 
 # Should be able to print dicts; in this case they aren't used
 # to lookup keywords in formats like %(foo)s
-print('%s' % {})
-print('%s' % ({},))
+print('%s' % {})      # dict treated as the single (positional) arg to %
+print('%s' % ({},))   # dict is the first (and only) arg in the positional arg tuple
+print('foo' % {})     # no error, dict treated as an empty map of named args
 
 # Cases when "*" used and there's not enough values total
 try:
@@ -65,7 +66,11 @@ except TypeError:
     print("TypeError")
 
 print("%(foo)s" % {"foo": "bar", "baz": False})
-print("%s %(foo)s %(foo)s" % {"foo": 1})
+print("%s %(foo)s %(foo)s" % {"foo": 1})  # dict consumed positionally, then used as map - ok
+try:
+    print("%(foo)s %s %(foo)s" % {"foo": 1})  # used as map, then positionally - not enough args
+except TypeError:
+    print("TypeError")
 try:
     print("%(foo)s" % {})
 except KeyError:
diff --git a/tests/basics/struct1.py b/tests/basics/struct1.py
index a18655517b..e473ffcc11 100644
--- a/tests/basics/struct1.py
+++ b/tests/basics/struct1.py
@@ -20,6 +20,8 @@ print(struct.pack("<h", 1))
 print(struct.pack(">h", 1))
 print(struct.pack("<b", 1))
 print(struct.pack(">b", 1))
+print(struct.pack("<x"))
+print(struct.pack(">x"))
 
 print(struct.pack("<bI", -128, 256))
 print(struct.pack(">bI", -128, 256))
@@ -29,6 +31,13 @@ print(struct.calcsize("97sI"))
 print(struct.unpack("<6sH", b"foo\0\0\0\x12\x34"))
 print(struct.pack("<6sH", b"foo", 10000))
 
+print(struct.calcsize("7xx"))
+print(struct.pack("7xx"))
+
+print(struct.calcsize(">bxI3xH"))
+print(struct.pack(">bxI3xH", 1, 2, 3))
+print(struct.unpack(">bxI3xH", b"\x01\0\0\0\0\x02\0\0\0\0\x03"))
+
 s = struct.pack("BHBI", 10, 100, 200, 300)
 v = struct.unpack("BHBI", s)
 print(v == (10, 100, 200, 300))
diff --git a/tests/extmod/select_ipoll.py b/tests/extmod/select_ipoll.py
new file mode 100644
index 0000000000..0b661c11c8
--- /dev/null
+++ b/tests/extmod/select_ipoll.py
@@ -0,0 +1,55 @@
+# Test select.ipoll().
+
+try:
+    import socket, select
+except ImportError:
+    print("SKIP")
+    raise SystemExit
+
+
+def print_poll_output(lst):
+    print([(type(obj), flags) for obj, flags in lst])
+
+
+poller = select.poll()
+
+# Use a new UDP socket for tests, which should be writable but not readable.
+try:
+    s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
+    s.bind(socket.getaddrinfo("127.0.0.1", 8000)[0][-1])
+except OSError:
+    print("SKIP")
+    raise SystemExit
+
+poller.register(s)
+
+# Basic polling.
+print_poll_output(poller.ipoll(0))
+
+# Pass in flags=1 for one-shot behaviour.
+print_poll_output(poller.ipoll(0, 1))
+
+# Socket should be deregistered and poll should return nothing.
+print_poll_output(poller.ipoll(0))
+
+# Create a second socket.
+s2 = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
+s2.bind(socket.getaddrinfo("127.0.0.1", 8001)[0][-1])
+
+# Register both sockets (to reset the first one).
+poller.register(s)
+poller.register(s2)
+
+# Basic polling with two sockets.
+print_poll_output(poller.ipoll(0))
+
+# Unregister the first socket, to test polling the remaining one.
+poller.unregister(s)
+print_poll_output(poller.ipoll(0))
+
+# Unregister the second socket, to test polling none.
+poller.unregister(s2)
+print_poll_output(poller.ipoll(0))
+
+s2.close()
+s.close()
diff --git a/tests/extmod/select_ipoll.py.exp b/tests/extmod/select_ipoll.py.exp
new file mode 100644
index 0000000000..cbeabdce90
--- /dev/null
+++ b/tests/extmod/select_ipoll.py.exp
@@ -0,0 +1,6 @@
+[(<class 'socket'>, 4)]
+[(<class 'socket'>, 4)]
+[]
+[(<class 'socket'>, 4), (<class 'socket'>, 4)]
+[(<class 'socket'>, 4)]
+[]
diff --git a/tests/extmod/select_poll_basic.py b/tests/extmod/select_poll_basic.py
index b36e16f018..0814d89ce9 100644
--- a/tests/extmod/select_poll_basic.py
+++ b/tests/extmod/select_poll_basic.py
@@ -16,6 +16,7 @@ poller.register(s)
 # "Registering a file descriptor that’s already registered is not an error,
 # and has the same effect as registering the descriptor exactly once."
 poller.register(s)
+poller.register(s, select.POLLIN | select.POLLOUT)
 
 # 2 args are mandatory unlike register()
 try:
diff --git a/tests/extmod/select_poll_custom.py b/tests/extmod/select_poll_custom.py
new file mode 100644
index 0000000000..b854a8a14d
--- /dev/null
+++ b/tests/extmod/select_poll_custom.py
@@ -0,0 +1,102 @@
+# Test custom pollable objects implemented in Python.
+
+from micropython import const
+
+try:
+    import socket, select, io
+except ImportError:
+    print("SKIP")
+    raise SystemExit
+
+_MP_STREAM_POLL = const(3)
+_MP_STREAM_GET_FILENO = const(10)
+
+_MP_STREAM_POLL_RD = const(0x0001)
+_MP_STREAM_POLL_WR = const(0x0004)
+
+
+def print_poll_output(lst):
+    print([(type(obj), flags) for obj, flags in lst])
+
+
+class CustomPollable(io.IOBase):
+    def __init__(self):
+        self.poll_state = 0
+
+    def ioctl(self, cmd, arg):
+        if cmd == _MP_STREAM_GET_FILENO:
+            # Bare-metal ports don't call this ioctl, so don't print it.
+            return -1
+
+        print("CustomPollable.ioctl", cmd, arg)
+        if cmd == _MP_STREAM_POLL:
+            if self.poll_state == "delay_rd":
+                self.poll_state = _MP_STREAM_POLL_RD
+                return 0
+            elif self.poll_state < 0:
+                return self.poll_state
+            else:
+                return self.poll_state & arg
+
+
+poller = select.poll()
+
+# Use a new UDP socket for tests, which should be writable but not readable.
+try:
+    s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
+    s.bind(socket.getaddrinfo("127.0.0.1", 8000)[0][-1])
+except OSError:
+    print("SKIP")
+    raise SystemExit
+
+x = CustomPollable()
+
+# Register both a file-descriptor-based object and a custom pure-Python object.
+poller.register(s)
+poller.register(x)
+
+# Modify the flags for the custom object.
+poller.modify(x, select.POLLIN)
+
+# Test polling.
+print_poll_output(poller.poll(0))
+x.poll_state = _MP_STREAM_POLL_WR
+print_poll_output(poller.poll(0))
+x.poll_state = _MP_STREAM_POLL_RD
+print_poll_output(poller.poll(0))
+
+# The custom object becomes readable only after being polled.
+poller.modify(s, select.POLLIN)
+x.poll_state = "delay_rd"
+print_poll_output(poller.poll())
+
+# The custom object returns an error.
+x.poll_state = -1000
+try:
+    poller.poll(0)
+except OSError as er:
+    print("OSError", er.errno)
+
+# Register then unregister a socket (a native stream), then test
+# that the Python object is still pollable.
+s2 = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
+x.poll_state = _MP_STREAM_POLL_RD
+poller.register(s2)
+poller.unregister(s2)
+print_poll_output(poller.poll())
+
+# Test registering and unregistering multiple times.
+for _ in range(2):
+    poller.unregister(s)
+    poller.unregister(x)
+    poller.register(s2)
+    poller.register(s, select.POLLIN)
+    poller.register(x, select.POLLIN)
+    poller.unregister(s2)
+    print_poll_output(poller.poll())
+
+# Clean up.
+poller.unregister(x)
+poller.unregister(s)
+s2.close()
+s.close()
diff --git a/tests/extmod/select_poll_custom.py.exp b/tests/extmod/select_poll_custom.py.exp
new file mode 100644
index 0000000000..d85508bab2
--- /dev/null
+++ b/tests/extmod/select_poll_custom.py.exp
@@ -0,0 +1,17 @@
+CustomPollable.ioctl 3 1
+[(<class 'socket'>, 4)]
+CustomPollable.ioctl 3 1
+[(<class 'socket'>, 4)]
+CustomPollable.ioctl 3 1
+[(<class 'socket'>, 4), (<class 'CustomPollable'>, 1)]
+CustomPollable.ioctl 3 1
+CustomPollable.ioctl 3 1
+[(<class 'CustomPollable'>, 1)]
+CustomPollable.ioctl 3 1
+OSError 1000
+CustomPollable.ioctl 3 1
+[(<class 'CustomPollable'>, 1)]
+CustomPollable.ioctl 3 1
+[(<class 'CustomPollable'>, 1)]
+CustomPollable.ioctl 3 1
+[(<class 'CustomPollable'>, 1)]
diff --git a/tests/extmod/select_poll_eintr.py b/tests/extmod/select_poll_eintr.py
new file mode 100644
index 0000000000..e1cbc2aaf5
--- /dev/null
+++ b/tests/extmod/select_poll_eintr.py
@@ -0,0 +1,50 @@
+# Test interruption of select.poll by EINTR signal, when
+# MICROPY_PY_SELECT_POSIX_OPTIMISATIONS is enabled.
+
+try:
+    import time, gc, select, socket, _thread
+
+    time.time_ns  # Check for time_ns on MicroPython
+    select.poll  # Raises AttributeError for CPython implementations without poll()
+except (ImportError, AttributeError):
+    print("SKIP")
+    raise SystemExit
+
+
+def thread_main():
+    lock.acquire()
+    time.sleep(0.2)
+    print("thread gc start")
+    # The unix gc.collect() implementation will raise EINTR on other threads.
+    # Could possibly use _thread._interrupt_main() instead if MicroPython had it.
+    gc.collect()
+    print("thread gc end")
+
+
+# Start a thread to interrupt the main thread during its call to poll.
+lock = _thread.allocate_lock()
+lock.acquire()
+_thread.start_new_thread(thread_main, ())
+
+# Use a new UDP socket for tests, which should be writable but not readable.
+s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
+s.bind(socket.getaddrinfo("127.0.0.1", 8000)[0][-1])
+
+# Create the poller object.
+poller = select.poll()
+poller.register(s, select.POLLIN)
+
+# Poll on the UDP socket for a set timeout, which should be reached.
+print("poll")
+lock.release()
+t0 = time.time_ns()
+result = poller.poll(400)
+dt_ms = (time.time_ns() - t0) / 1e6
+print("result:", result)
+if 380 <= dt_ms <= 600:
+    print("dt in range")
+else:
+    print("dt not in range:", dt_ms)
+
+# Clean up.
+s.close()
diff --git a/tests/extmod/select_poll_fd.py b/tests/extmod/select_poll_fd.py
new file mode 100644
index 0000000000..fab9c0e0e9
--- /dev/null
+++ b/tests/extmod/select_poll_fd.py
@@ -0,0 +1,44 @@
+# Test select.poll in combination with file descriptors.
+
+try:
+    import select, errno
+
+    select.poll  # Raises AttributeError for CPython implementations without poll()
+except (ImportError, AttributeError):
+    print("SKIP")
+    raise SystemExit
+
+# Check that poll supports registering file descriptors (integers).
+try:
+    select.poll().register(0)
+except OSError:
+    print("SKIP")
+    raise SystemExit
+
+# Register invalid file descriptor.
+try:
+    select.poll().register(-1)
+except ValueError:
+    print("ValueError")
+
+# Test polling stdout, it should be writable.
+poller = select.poll()
+poller.register(1)
+poller.modify(1, select.POLLOUT)
+print(poller.poll())
+
+# Unregister then re-register.
+poller.unregister(1)
+poller.register(1, select.POLLIN)
+
+# Poll for input, should return an empty list.
+print(poller.poll(0))
+
+# Test registering a very large number of file descriptors.
+poller = select.poll()
+for fd in range(6000):
+    poller.register(fd)
+try:
+    poller.poll()
+except OSError as er:
+    print(er.errno == errno.EINVAL)
diff --git a/tests/extmod/select_poll_udp.py b/tests/extmod/select_poll_udp.py
index 336f987c12..133871b1a4 100644
--- a/tests/extmod/select_poll_udp.py
+++ b/tests/extmod/select_poll_udp.py
@@ -8,9 +8,13 @@ except (ImportError, AttributeError):
     print("SKIP")
     raise SystemExit
 
+try:
+    s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
+    s.bind(socket.getaddrinfo("127.0.0.1", 8000)[0][-1])
+except OSError:
+    print("SKIP")
+    raise SystemExit
 
-s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
-s.bind(socket.getaddrinfo("127.0.0.1", 8000)[0][-1])
 poll = select.poll()
 
 # UDP socket should not be readable
diff --git a/tests/extmod/socket_udp_nonblock.py b/tests/extmod/socket_udp_nonblock.py
index f7ce5f3444..1e74e2917d 100644
--- a/tests/extmod/socket_udp_nonblock.py
+++ b/tests/extmod/socket_udp_nonblock.py
@@ -6,9 +6,13 @@ except ImportError:
     print("SKIP")
     raise SystemExit
 
+try:
+    s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
+    s.bind(socket.getaddrinfo("127.0.0.1", 8000)[0][-1])
+except OSError:
+    print("SKIP")
+    raise SystemExit
 
-s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
-s.bind(socket.getaddrinfo("127.0.0.1", 8000)[0][-1])
 s.settimeout(0)
 
 try:
diff --git a/tests/extmod/ssl_ioctl.py b/tests/extmod/ssl_ioctl.py
new file mode 100644
index 0000000000..4db7c2df82
--- /dev/null
+++ b/tests/extmod/ssl_ioctl.py
@@ -0,0 +1,31 @@
+# Test SSL ioctl method.
+# Direct access to this method is only available if MICROPY_UNIX_COVERAGE is enabled.
+
+try:
+    import io, ssl
+
+    io.BytesIO
+except (ImportError, AttributeError):
+    print("SKIP")
+    raise SystemExit
+
+_MP_STREAM_POLL = 3
+_MP_STREAM_CLOSE = 4
+_MP_STREAM_GET_FILENO = 10
+
+s = ssl.wrap_socket(io.BytesIO(), server_side=1, do_handshake=0)
+
+if not hasattr(s, "ioctl"):
+    print("SKIP")
+    raise SystemExit
+
+# These ioctl's should be unsupported.
+for request in (-1, 0, _MP_STREAM_GET_FILENO):
+    try:
+        s.ioctl(request, 0)
+    except OSError:
+        print(request, "OSError")
+
+# These ioctl's should be supported.
+for request in (_MP_STREAM_CLOSE, _MP_STREAM_POLL, _MP_STREAM_CLOSE):
+    print(request, s.ioctl(request, 0))
diff --git a/tests/extmod/ssl_ioctl.py.exp b/tests/extmod/ssl_ioctl.py.exp
new file mode 100644
index 0000000000..22208b00cc
--- /dev/null
+++ b/tests/extmod/ssl_ioctl.py.exp
@@ -0,0 +1,6 @@
+-1 OSError
+0 OSError
+10 OSError
+4 0
+3 32
+4 0
diff --git a/tests/io/file_stdio.py b/tests/io/file_stdio.py
index cbdb070163..d714bffd4d 100644
--- a/tests/io/file_stdio.py
+++ b/tests/io/file_stdio.py
@@ -2,3 +2,4 @@ import sys
 
 print(sys.stdin.fileno())
 print(sys.stdout.fileno())
+print(sys.stderr.fileno())
diff --git a/tests/io/file_stdio2.py b/tests/io/file_stdio2.py
new file mode 100644
index 0000000000..5b8a5a7692
--- /dev/null
+++ b/tests/io/file_stdio2.py
@@ -0,0 +1,65 @@
+# Test sys.std*.buffer objects.
+
+import sys
+
+try:
+    sys.stdout.buffer
+    sys.stdin.buffer
+    sys.stderr.buffer
+except AttributeError:
+    print("SKIP")
+    raise SystemExit
+
+
+# force cpython to flush after every print
+# this is to sequence stdout and stderr
+def print_flush(*args, **kwargs):
+    try:
+        print(*args, **kwargs, flush=True)
+    except TypeError:
+        print(*args, **kwargs)
+
+
+print_flush("==stdin==")
+print_flush(sys.stdin.buffer.fileno())
+
+
+print_flush("==stdout==")
+print_flush(sys.stdout.buffer.fileno())
+n_text = sys.stdout.write("The quick brown fox jumps over the lazy dog\n")
+sys.stdout.flush()
+n_binary = sys.stdout.buffer.write("The quick brown fox jumps over the lazy dog\n".encode("utf-8"))
+sys.stdout.buffer.flush()
+print_flush("n_text:{} n_binary:{}".format(n_text, n_binary))
+
+# temporarily disabling unicode tests until future PR which fixes unicode write character count
+# n_text = sys.stdout.write("🚀")
+# sys.stdout.flush()
+# n_binary = sys.stdout.buffer.write("🚀".encode("utf-8"))
+# sys.stdout.buffer.flush()
+# print_flush("")
+# print_flush("n_text:{} n_binary:{}".format(n_text, n_binary))
+# n_text = sys.stdout.write("1🚀2a3α4b5β6c7γ8d9δ0ぁ1🙐")
+# sys.stdout.flush()
+# n_binary = sys.stdout.buffer.write("1🚀2a3α4b5β6c7γ8d9δ0ぁ1🙐".encode("utf-8"))
+# sys.stdout.buffer.flush()
+# print_flush("")
+# print_flush("n_text:{} n_binary:{}".format(n_text, n_binary))
+
+
+print_flush("==stderr==")
+print_flush(sys.stderr.buffer.fileno())
+n_text = sys.stderr.write("The quick brown fox jumps over the lazy dog\n")
+sys.stderr.flush()
+n_binary = sys.stderr.buffer.write("The quick brown fox jumps over the lazy dog\n".encode("utf-8"))
+sys.stderr.buffer.flush()
+print_flush("n_text:{} n_binary:{}".format(n_text, n_binary))
+
+# temporarily disabling unicode tests until future PR which fixes unicode write character count
+# n_text = sys.stderr.write("🚀")
+# sys.stderr.flush()
+# n_binary = sys.stderr.buffer.write("🚀".encode("utf-8"))
+# sys.stderr.buffer.flush()
+# print_flush("")
+# print_flush("n_text:{} n_binary:{}".format(n_text, n_binary))
+# print_flush("")
diff --git a/tests/micropython/import_mpy_native_gc.py b/tests/micropython/import_mpy_native_gc.py
index 5a3855dc7d..5f2a2a6f45 100644
--- a/tests/micropython/import_mpy_native_gc.py
+++ b/tests/micropython/import_mpy_native_gc.py
@@ -47,6 +47,10 @@ class UserFS:
 
 # Pre-compiled examples/natmod/features0 example for various architectures, keyed
 # by the required value of sys.implementation._mpy (without sub-version).
+# cd examples/natmod/features0
+# make clean
+# make ARCH=x64 # or ARCH=armv6m
+# cat features0.mpy | python -c 'import sys; print(sys.stdin.buffer.read())'
 features0_file_contents = {
     # -march=x64
     0x806: b'M\x06\x09\x1f\x02\x004build/features0.native.mpy\x00\x12factorial\x00\x8a\x02\xe9/\x00\x00\x00SH\x8b\x1d\x83\x00\x00\x00\xbe\x02\x00\x00\x00\xffS\x18\xbf\x01\x00\x00\x00H\x85\xc0u\x0cH\x8bC \xbe\x02\x00\x00\x00[\xff\xe0H\x0f\xaf\xf8H\xff\xc8\xeb\xe6ATUSH\x8b\x1dQ\x00\x00\x00H\x8bG\x08L\x8bc(H\x8bx\x08A\xff\xd4H\x8d5+\x00\x00\x00H\x89\xc5H\x8b\x059\x00\x00\x00\x0f\xb7x\x02\xffShH\x89\xefA\xff\xd4H\x8b\x03[]A\\\xc3\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x05\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x10\x11$\r&\xa3 \x01"\xff',
diff --git a/tests/misc/sys_settrace_features.py b/tests/misc/sys_settrace_features.py
index 8a38b7534f..8ca6b382e3 100644
--- a/tests/misc/sys_settrace_features.py
+++ b/tests/misc/sys_settrace_features.py
@@ -22,7 +22,9 @@ def print_stacktrace(frame, level=0):
             frame.f_code.co_name,
             # Keep just the filename.
             "sys_settrace_" + frame.f_code.co_filename.split("sys_settrace_")[-1],
-            frame.f_lineno,
+            max(
+                1, frame.f_lineno
+            ),  # CPython 3.11 emits `0` where CPython 3.6 emits `1` for the "call" event corresponding to import.
         )
     )
 
@@ -65,6 +67,11 @@ def trace_tick_handler(frame, event, arg):
     if any(name in frame_name for name in to_ignore):
         return
 
+    # Lines 4,5,7 create the `const` lambda, and line `15` is a `_X = const()` which
+    # MicroPython will not see as it's optimised out.
+    if "sys_settrace_importme" in frame.f_code.co_filename and frame.f_lineno in (4, 5, 7, 15):
+        return trace_tick_handler
+
     print("### trace_handler::main event:", event)
     __prof__.trace_tick(frame, event, arg)
 
diff --git a/tests/misc/sys_settrace_subdir/sys_settrace_importme.py b/tests/misc/sys_settrace_subdir/sys_settrace_importme.py
index de561ef217..fdfa06134e 100644
--- a/tests/misc/sys_settrace_subdir/sys_settrace_importme.py
+++ b/tests/misc/sys_settrace_subdir/sys_settrace_importme.py
@@ -3,12 +3,18 @@ print("Yep, I got imported.")
 try:
     x = const(1)
 except NameError:
-    print("const not defined")
+    # Either running on CPython or MICROPY_COMP_CONST disabled.
+    const = lambda x: x
 
-const = lambda x: x
 
+# No const optimisation.
 _CNT01 = "CONST01"
+
+# Const assigned to an underscore name. Invisible to MicroPython with
+# MICROPY_COMP_CONST enabled.
 _CNT02 = const(123)
+
+# Consts assigned to regular name, executed normally.
 A123 = const(123)
 a123 = const(123)
 
diff --git a/tests/multi_net/asyncio_tcp_close_write.py b/tests/multi_net/asyncio_tcp_close_write.py
index d1892fe895..ea206c9219 100644
--- a/tests/multi_net/asyncio_tcp_close_write.py
+++ b/tests/multi_net/asyncio_tcp_close_write.py
@@ -33,7 +33,7 @@ async def tcp_server():
     print("server running")
     multitest.next()
     async with server:
-        await asyncio.wait_for(ev.wait(), 5)
+        await asyncio.wait_for(ev.wait(), 10)
 
 
 async def tcp_client():
diff --git a/tests/multi_net/asyncio_tcp_readall.py b/tests/multi_net/asyncio_tcp_readall.py
index 66ad97549c..45eac229d2 100644
--- a/tests/multi_net/asyncio_tcp_readall.py
+++ b/tests/multi_net/asyncio_tcp_readall.py
@@ -14,7 +14,7 @@ async def handle_connection(reader, writer):
     await writer.drain()
 
     # Split the first 2 bytes up so the client must wait for the second one
-    await asyncio.sleep(0.1)
+    await asyncio.sleep(1)
 
     writer.write(b"b")
     await writer.drain()
@@ -37,7 +37,7 @@ async def tcp_server():
     print("server running")
     multitest.next()
     async with server:
-        await asyncio.wait_for(ev.wait(), 2)
+        await asyncio.wait_for(ev.wait(), 10)
 
 
 async def tcp_client():
diff --git a/tests/multi_net/asyncio_tcp_readexactly.py b/tests/multi_net/asyncio_tcp_readexactly.py
index 2c8df1f30a..4024e23fed 100644
--- a/tests/multi_net/asyncio_tcp_readexactly.py
+++ b/tests/multi_net/asyncio_tcp_readexactly.py
@@ -14,7 +14,7 @@ async def handle_connection(reader, writer):
     await writer.drain()
 
     # Split the first 2 bytes up so the client must wait for the second one
-    await asyncio.sleep(0.1)
+    await asyncio.sleep(1)
 
     writer.write(b"b")
     await writer.drain()
diff --git a/tests/run-tests.py b/tests/run-tests.py
index 019b30189f..de886b8ae7 100755
--- a/tests/run-tests.py
+++ b/tests/run-tests.py
@@ -709,7 +709,9 @@ def run_tests(pyb, tests, args, result_dir, num_threads=1):
             # run CPython to work out expected output
             try:
                 output_expected = subprocess.check_output(
-                    CPYTHON3_CMD + [os.path.abspath(test_file)], cwd=os.path.dirname(test_file)
+                    CPYTHON3_CMD + [os.path.abspath(test_file)],
+                    cwd=os.path.dirname(test_file),
+                    stderr=subprocess.STDOUT,
                 )
                 if args.write_exp:
                     with open(test_file_expected, "wb") as f:
diff --git a/tests/thread/thread_ident1.py b/tests/thread/thread_ident1.py
index 390193accc..8e106cd317 100644
--- a/tests/thread/thread_ident1.py
+++ b/tests/thread/thread_ident1.py
@@ -5,7 +5,11 @@
 import _thread
 
 
+tid = None
+
+
 def thread_entry():
+    global tid
     tid = _thread.get_ident()
     print("thread", type(tid) == int, tid != 0, tid != tid_main)
     global finished
@@ -16,8 +20,9 @@ tid_main = _thread.get_ident()
 print("main", type(tid_main) == int, tid_main != 0)
 
 finished = False
-_thread.start_new_thread(thread_entry, ())
+new_tid = _thread.start_new_thread(thread_entry, ())
 
 while not finished:
     pass
-print("done")
+
+print("done", type(new_tid) == int, new_tid == tid)
diff --git a/tests/unix/mod_os.py b/tests/unix/mod_os.py
index 17554d9375..f69fa45b2b 100644
--- a/tests/unix/mod_os.py
+++ b/tests/unix/mod_os.py
@@ -12,7 +12,7 @@ os.unsetenv("TEST_VARIABLE")
 print(os.getenv("TEST_VARIABLE"))
 print(os.getenv("TEST_VARIABLE", "TEST_DEFAULT_VALUE"))
 
-print(os.system("true"))
+print(os.system("exit 0"))
 
 rand = os.urandom(4)
 print(type(rand) is bytes, len(rand))
diff --git a/tools/autobuild/autobuild.sh b/tools/autobuild/autobuild.sh
index b3c9c19c7c..e1f2287ee5 100755
--- a/tools/autobuild/autobuild.sh
+++ b/tools/autobuild/autobuild.sh
@@ -60,9 +60,9 @@ FW_TAG="-$FW_DATE-unstable-$FW_GIT"
 
 # build new firmware
 cd ports/cc3200
-${AUTODIR}/build-cc3200-latest.sh ${FW_TAG} ${LOCAL_FIRMWARE}
+build_cc3200_boards ${FW_TAG} ${LOCAL_FIRMWARE}
 cd ../esp8266
-${AUTODIR}/build-esp8266-latest.sh ${FW_TAG} ${LOCAL_FIRMWARE}
+build_esp8266_boards ${FW_TAG} ${LOCAL_FIRMWARE}
 cd ../esp32
 (source ${IDF_PATH_V50}/export.sh && build_esp32_boards ${FW_TAG} ${LOCAL_FIRMWARE})
 cd ../mimxrt
@@ -77,7 +77,6 @@ cd ../samd
 build_samd_boards ${FW_TAG} ${LOCAL_FIRMWARE}
 cd ../stm32
 build_stm32_boards ${FW_TAG} ${LOCAL_FIRMWARE}
-${AUTODIR}/build-stm32-extra.sh ${FW_TAG} ${LOCAL_FIRMWARE}
 
 popd
 
diff --git a/tools/autobuild/build-boards.sh b/tools/autobuild/build-boards.sh
index 689444a988..2b323ba9b0 100755
--- a/tools/autobuild/build-boards.sh
+++ b/tools/autobuild/build-boards.sh
@@ -3,8 +3,36 @@
 # The functions in this file can be run independently to build boards.
 # For example:
 #
-#   $ source build-boards.sh
-#   $ MICROPY_AUTOBUILD_MAKE=make build_rp2_boards -latest /tmp
+#   $ source tools/autobuild/build-boards.sh
+#   $ cd ports/rp2
+#   $ MICROPY_AUTOBUILD_MAKE="make -j8" build_rp2_boards -latest /tmp
+#
+# Or to build a single board:
+#
+#   $ source tools/autobuild/build-boards.sh
+#   $ cd ports/rp2
+#   $ MICROPY_AUTOBUILD_MAKE="make -j8" build_board boards/PICO/board.json -latest /tmp uf2
+
+function copy_artefacts {
+    local dest_dir=$1
+    local descr=$2
+    local fw_tag=$3
+    local build_dir=$4
+    shift 4
+
+    for ext in $@; do
+        dest=$dest_dir/$descr$fw_tag.$ext
+        if [ -r $build_dir/firmware.$ext ]; then
+            mv $build_dir/firmware.$ext $dest
+        elif [ -r $build_dir/micropython.$ext ]; then
+            # esp32 has micropython.elf, etc
+            mv $build_dir/micropython.$ext $dest
+        elif [ $ext = app-bin -a -r $build_dir/micropython.bin ]; then
+            # esp32 has micropython.bin which is just the application
+            mv $build_dir/micropython.bin $dest
+        fi
+    done
+}
 
 function build_board {
     # check/get parameters
@@ -13,33 +41,29 @@ function build_board {
         return 1
     fi
 
-    board_json=$1
-    fw_tag=$2
-    dest_dir=$3
-    shift
-    shift
-    shift
+    local board_json=$1
+    local fw_tag=$2
+    local dest_dir=$3
+    shift 3
 
-    board=$(echo $board_json | awk -F '/' '{ print $2 }')
-    descr=$(cat $board_json | python3 -c "import json,sys; print(json.load(sys.stdin).get('id', '$board'))")
-    build_dir=/tmp/micropython-build-$board
+    local board=$(echo $board_json | awk -F '/' '{ print $2 }')
+    local descr=$(cat $board_json | python3 -c "import json,sys; print(json.load(sys.stdin).get('id', '$board'))")
 
+    # Build the "default" variant. For most boards this is the only thing we build.
     echo "building $descr $board"
-    $MICROPY_AUTOBUILD_MAKE BOARD=$board BUILD=$build_dir && (
-        for ext in $@; do
-            dest=$dest_dir/$descr$fw_tag.$ext
-            if [ -r $build_dir/firmware.$ext ]; then
-                mv $build_dir/firmware.$ext $dest
-            elif [ -r $build_dir/micropython.$ext ]; then
-                # esp32 has micropython.elf, etc
-                mv $build_dir/micropython.$ext $dest
-            elif [ $ext = app-bin -a -r $build_dir/micropython.bin ]; then
-                # esp32 has micropython.bin which is just the application
-                mv $build_dir/micropython.bin $dest
-            fi
-        done
-    )
+    local build_dir=/tmp/micropython-build-$board
+    $MICROPY_AUTOBUILD_MAKE BOARD=$board BUILD=$build_dir && copy_artefacts $dest_dir $descr $fw_tag $build_dir $@
     rm -rf $build_dir
+
+    # Query variants from board.json and build them. Ignore the special "IDF3"
+    # variant for ESP32 boards (this allows the downloads page to still have
+    # the idf3 files for older releases that used to be explicitly built).
+    for variant in `cat $board_json | python3 -c "import json,sys; print(' '.join(v for v in json.load(sys.stdin).get('variants', {}).keys() if v != 'IDF3'))"`; do
+        local variant_build_dir=$build_dir-$variant
+        echo "building variant $descr $board $variant"
+        $MICROPY_AUTOBUILD_MAKE BOARD=$board BOARD_VARIANT=$variant BUILD=$variant_build_dir && copy_artefacts $dest_dir $descr-$variant $fw_tag $variant_build_dir $@
+        rm -rf $variant_build_dir
+    done
 }
 
 function build_boards {
@@ -49,7 +73,7 @@ function build_boards {
         return 1
     fi
 
-    check_file=$1
+    local check_file=$1
     shift
 
     # check we are in the correct directory
@@ -64,10 +88,18 @@ function build_boards {
     done
 }
 
+function build_cc3200_boards {
+    build_boards hal/cc3200_hal.c $1 $2 zip
+}
+
 function build_esp32_boards {
     build_boards modesp32.c $1 $2 bin elf map uf2 app-bin
 }
 
+function build_esp8266_boards {
+    build_boards modesp.c $1 $2 bin elf map
+}
+
 function build_mimxrt_boards {
     build_boards modmimxrt.c $1 $2 bin hex
 }
diff --git a/tools/autobuild/build-cc3200-latest.sh b/tools/autobuild/build-cc3200-latest.sh
deleted file mode 100755
index 0cbdb9c428..0000000000
--- a/tools/autobuild/build-cc3200-latest.sh
+++ /dev/null
@@ -1,32 +0,0 @@
-#!/bin/bash
-
-# function for building firmware
-function do_build() {
-    descr=$1
-    board=$2
-    shift
-    shift
-    echo "building $descr $board"
-    build_dir=/tmp/cc3200-build-$board
-    $MICROPY_AUTOBUILD_MAKE $@ BTARGET=application BOARD=$board BUILD=$build_dir || exit 1
-    zip $dest_dir/$descr$fw_tag.zip $build_dir/mcuimg.bin
-    rm -rf $build_dir
-}
-
-# check/get parameters
-if [ $# != 2 ]; then
-    echo "usage: $0 <fw-tag> <dest-dir>"
-    exit 1
-fi
-
-fw_tag=$1
-dest_dir=$2
-
-# check we are in the correct directory
-if [ ! -r application.mk ]; then
-    echo "must be in cc3200 directory"
-    exit 1
-fi
-
-# build the versions
-do_build wipy WIPY
diff --git a/tools/autobuild/build-esp8266-latest.sh b/tools/autobuild/build-esp8266-latest.sh
deleted file mode 100755
index 1972e85fcd..0000000000
--- a/tools/autobuild/build-esp8266-latest.sh
+++ /dev/null
@@ -1,61 +0,0 @@
-#!/bin/bash
-
-PYTHON3=python3
-yaota8266=$HOME/yaota8266
-
-# for debugging
-#exec &> /tmp/esp-log-$$.txt
-
-# function for building firmware
-function do_build() {
-    descr=$1
-    board=$2
-    shift
-    shift
-    echo "building $descr $board"
-    build_dir=/tmp/esp8266-build-$board
-    $MICROPY_AUTOBUILD_MAKE $@ BOARD=$board BUILD=$build_dir || exit 1
-    mv $build_dir/firmware-combined.bin $dest_dir/$descr$fw_tag.bin
-    mv $build_dir/firmware.elf $dest_dir/$descr$fw_tag.elf
-    mv $build_dir/firmware.map $dest_dir/$descr$fw_tag.map
-    rm -rf $build_dir
-}
-
-function do_build_ota() {
-    descr=$1
-    board=$2
-    shift
-    shift
-    echo "building $descr $board"
-    build_dir=/tmp/esp8266-build-$board
-    $MICROPY_AUTOBUILD_MAKE $@ BOARD=$board BUILD=$build_dir || exit 1
-    cat $yaota8266/yaota8266.bin $build_dir/firmware-ota.bin > $dest_dir/$descr$fw_tag.bin
-    pushd $yaota8266/ota-client
-    $PYTHON3 ota_client.py sign $build_dir/firmware-ota.bin
-    popd
-    mv $build_dir/firmware-ota.bin.ota $dest_dir/$descr$fw_tag.ota
-    mv $build_dir/firmware.elf $dest_dir/$descr$fw_tag.elf
-    mv $build_dir/firmware.map $dest_dir/$descr$fw_tag.map
-    rm -rf $build_dir
-}
-
-# check/get parameters
-if [ $# != 2 ]; then
-    echo "usage: $0 <fw-tag> <dest-dir>"
-    exit 1
-fi
-
-fw_tag=$1
-dest_dir=$2
-
-# check we are in the correct directory
-if [ ! -r boards/esp8266_common.ld ]; then
-    echo "must be in esp8266 directory"
-    exit 1
-fi
-
-# build the versions
-do_build esp8266 GENERIC
-do_build esp8266-512k GENERIC_512K
-do_build esp8266-1m GENERIC_1M
-do_build_ota esp8266-ota GENERIC_1M ota
diff --git a/tools/autobuild/build-stm32-extra.sh b/tools/autobuild/build-stm32-extra.sh
deleted file mode 100755
index 887e3cd246..0000000000
--- a/tools/autobuild/build-stm32-extra.sh
+++ /dev/null
@@ -1,39 +0,0 @@
-#!/bin/bash
-# Build additional variants of pyboard firmware (base variants are built by build-boards.sh).
-
-# function for building firmware
-function do_build() {
-    descr=$1
-    board=$2
-    shift
-    shift
-    for variant in `$MICROPY_AUTOBUILD_MAKE BOARD=$board query-variants | grep VARIANTS: | cut -d' ' -f2-`; do
-        target=$descr-$variant
-        echo "building $target $board"
-        build_dir=/tmp/stm-build-$board-$variant
-        $MICROPY_AUTOBUILD_MAKE $@ BOARD=$board BOARD_VARIANT=$variant BUILD=$build_dir || exit 1
-        mv $build_dir/firmware.dfu $dest_dir/$target$fw_tag.dfu
-        mv $build_dir/firmware.hex $dest_dir/$target$fw_tag.hex
-        rm -rf $build_dir
-    done
-}
-
-# check/get parameters
-if [ $# != 2 ]; then
-    echo "usage: $0 <fw-tag> <dest-dir>"
-    exit 1
-fi
-
-fw_tag=$1
-dest_dir=$2
-
-# check we are in the correct directory
-if [ ! -r modpyb.c ]; then
-    echo "must be in stm directory"
-    exit 1
-fi
-
-# build the variants for each board
-do_build pybv10 PYBV10
-do_build pybv11 PYBV11
-do_build pyblitev10 PYBLITEV10
diff --git a/tools/ci.sh b/tools/ci.sh
index 98e78dc78a..5ce742b01b 100755
--- a/tools/ci.sh
+++ b/tools/ci.sh
@@ -129,9 +129,9 @@ function ci_esp32_build {
     make ${MAKEOPTS} -C ports/esp32 \
         USER_C_MODULES=../../../examples/usercmodule/micropython.cmake \
         FROZEN_MANIFEST=$(pwd)/ports/esp32/boards/manifest_test.py
-    make ${MAKEOPTS} -C ports/esp32 BOARD=GENERIC_C3
-    make ${MAKEOPTS} -C ports/esp32 BOARD=GENERIC_S2
-    make ${MAKEOPTS} -C ports/esp32 BOARD=GENERIC_S3
+    make ${MAKEOPTS} -C ports/esp32 BOARD=ESP32_GENERIC_C3
+    make ${MAKEOPTS} -C ports/esp32 BOARD=ESP32_GENERIC_S2
+    make ${MAKEOPTS} -C ports/esp32 BOARD=ESP32_GENERIC_S3
 
     # Test building native .mpy with xtensawin architecture.
     ci_native_mpy_modules_build xtensawin
@@ -155,9 +155,9 @@ function ci_esp8266_path {
 function ci_esp8266_build {
     make ${MAKEOPTS} -C mpy-cross
     make ${MAKEOPTS} -C ports/esp8266 submodules
-    make ${MAKEOPTS} -C ports/esp8266
-    make ${MAKEOPTS} -C ports/esp8266 BOARD=GENERIC_512K
-    make ${MAKEOPTS} -C ports/esp8266 BOARD=GENERIC_1M
+    make ${MAKEOPTS} -C ports/esp8266 BOARD=ESP8266_GENERIC
+    make ${MAKEOPTS} -C ports/esp8266 BOARD=ESP8266_GENERIC BOARD_VARIANT=FLASH_512K
+    make ${MAKEOPTS} -C ports/esp8266 BOARD=ESP8266_GENERIC BOARD_VARIANT=FLASH_1M
 }
 
 ########################################################################################
@@ -204,10 +204,10 @@ function ci_nrf_build {
     ports/nrf/drivers/bluetooth/download_ble_stack.sh s140_nrf52_6_1_1
     make ${MAKEOPTS} -C mpy-cross
     make ${MAKEOPTS} -C ports/nrf submodules
-    make ${MAKEOPTS} -C ports/nrf BOARD=pca10040
-    make ${MAKEOPTS} -C ports/nrf BOARD=microbit
-    make ${MAKEOPTS} -C ports/nrf BOARD=pca10056 SD=s140
-    make ${MAKEOPTS} -C ports/nrf BOARD=pca10090
+    make ${MAKEOPTS} -C ports/nrf BOARD=PCA10040
+    make ${MAKEOPTS} -C ports/nrf BOARD=MICROBIT
+    make ${MAKEOPTS} -C ports/nrf BOARD=PCA10056 SD=s140
+    make ${MAKEOPTS} -C ports/nrf BOARD=PCA10090
 }
 
 ########################################################################################
@@ -272,8 +272,8 @@ function ci_rp2_build {
     make ${MAKEOPTS} -C mpy-cross
     make ${MAKEOPTS} -C ports/rp2 submodules
     make ${MAKEOPTS} -C ports/rp2
-    make ${MAKEOPTS} -C ports/rp2 BOARD=PICO_W submodules
-    make ${MAKEOPTS} -C ports/rp2 BOARD=PICO_W USER_C_MODULES=../../examples/usercmodule/micropython.cmake
+    make ${MAKEOPTS} -C ports/rp2 BOARD=RPI_PICO_W submodules
+    make ${MAKEOPTS} -C ports/rp2 BOARD=RPI_PICO_W USER_C_MODULES=../../examples/usercmodule/micropython.cmake
     make ${MAKEOPTS} -C ports/rp2 BOARD=W5100S_EVB_PICO submodules
     make ${MAKEOPTS} -C ports/rp2 BOARD=W5100S_EVB_PICO
 
@@ -425,6 +425,7 @@ function ci_native_mpy_modules_build {
     make -C examples/natmod/features1 ARCH=$arch
     make -C examples/natmod/features2 ARCH=$arch
     make -C examples/natmod/features3 ARCH=$arch
+    make -C examples/natmod/features4 ARCH=$arch
     make -C examples/natmod/btree ARCH=$arch
     make -C examples/natmod/deflate ARCH=$arch
     make -C examples/natmod/framebuf ARCH=$arch
diff --git a/tools/codeformat.py b/tools/codeformat.py
index 517aced37a..761bde3a81 100755
--- a/tools/codeformat.py
+++ b/tools/codeformat.py
@@ -60,6 +60,8 @@ PATHS = [
 EXCLUSIONS = [
     # The cc3200 port is not fully formatted yet.
     "ports/cc3200/*/*.[ch]",
+    # ESP-IDF downloads 3rd party code.
+    "ports/esp32/managed_components/*",
     # The nrf port is not fully formatted yet.
     "ports/nrf/boards/*.[ch]",
     "ports/nrf/device/*.[ch]",
@@ -88,6 +90,7 @@ EXCLUSIONS = [
 TOP = os.path.abspath(os.path.join(os.path.dirname(__file__), ".."))
 
 UNCRUSTIFY_CFG = os.path.join(TOP, "tools/uncrustify.cfg")
+PYPROJECT_TOML = os.path.join(TOP, "pyproject.toml")
 
 C_EXTS = (
     ".c",
@@ -206,7 +209,7 @@ def main():
 
     # Format Python files with black.
     if format_py:
-        command = ["black", "--fast", "--line-length=99"]
+        command = ["black", "--fast", "--config={}".format(PYPROJECT_TOML)]
         if args.v:
             command.append("-v")
         else:
diff --git a/tools/metrics.py b/tools/metrics.py
index 13161e9b9a..95156e3012 100755
--- a/tools/metrics.py
+++ b/tools/metrics.py
@@ -68,8 +68,8 @@ port_data = {
     "3": PortData("esp32", "esp32", "build-GENERIC/micropython.elf"),
     "x": PortData("mimxrt", "mimxrt", "build-TEENSY40/firmware.elf"),
     "e": PortData("renesas-ra", "renesas-ra", "build-EK_RA6M2/firmware.elf"),
-    "r": PortData("nrf", "nrf", "build-pca10040/firmware.elf"),
-    "p": PortData("rp2", "rp2", "build-PICO/firmware.elf"),
+    "r": PortData("nrf", "nrf", "build-PCA10040/firmware.elf"),
+    "p": PortData("rp2", "rp2", "build-RPI_PICO/firmware.elf"),
     "d": PortData("samd", "samd", "build-ADAFRUIT_ITSYBITSY_M4_EXPRESS/firmware.elf"),
 }
 
diff --git a/tools/mpremote/mpremote/commands.py b/tools/mpremote/mpremote/commands.py
index de12aa0bb1..aae612765b 100644
--- a/tools/mpremote/mpremote/commands.py
+++ b/tools/mpremote/mpremote/commands.py
@@ -238,6 +238,7 @@ def do_resume(state, _args=None):
 
 def do_soft_reset(state, _args=None):
     state.ensure_raw_repl(soft_reset=True)
+    state.did_action()
 
 
 def do_rtc(state, args):
diff --git a/tools/mpy-tool.py b/tools/mpy-tool.py
index 7f581d0b13..5ef69b267a 100755
--- a/tools/mpy-tool.py
+++ b/tools/mpy-tool.py
@@ -33,9 +33,9 @@ if platform.python_version_tuple()[0] == "2":
 
     str_cons = lambda val, enc=None: str(val)
     bytes_cons = lambda val, enc=None: bytearray(val)
-    is_str_type = lambda o: type(o) is str
+    is_str_type = lambda o: isinstance(o, str)
     is_bytes_type = lambda o: type(o) is bytearray
-    is_int_type = lambda o: type(o) is int or type(o) is long
+    is_int_type = lambda o: isinstance(o, int) or isinstance(o, long)  # noqa: F821
 
     def hexlify_to_str(b):
         x = hexlify_py2(b)
@@ -46,9 +46,9 @@ else:
 
     str_cons = str
     bytes_cons = bytes
-    is_str_type = lambda o: type(o) is str
-    is_bytes_type = lambda o: type(o) is bytes
-    is_int_type = lambda o: type(o) is int
+    is_str_type = lambda o: isinstance(o, str)
+    is_bytes_type = lambda o: isinstance(o, bytes)
+    is_int_type = lambda o: isinstance(o, int)
 
     def hexlify_to_str(b):
         return str(hexlify(b, ":"), "ascii")
@@ -756,7 +756,7 @@ class CompiledModule:
                 const_int_content += (digs.count(",") + 1) * bits_per_dig // 8
                 const_obj_content += 4 * 4
                 return "MP_ROM_PTR(&%s)" % obj_name
-        elif type(obj) is float:
+        elif isinstance(obj, float):
             macro_name = "%s_macro" % obj_name
             print(
                 "#if MICROPY_OBJ_REPR == MICROPY_OBJ_REPR_A || MICROPY_OBJ_REPR == MICROPY_OBJ_REPR_B"
@@ -777,7 +777,7 @@ class CompiledModule:
             print("#endif")
             const_obj_content += 3 * 4
             return macro_name
-        elif type(obj) is complex:
+        elif isinstance(obj, complex):
             print(
                 "static const mp_obj_complex_t %s = {{&mp_type_complex}, (mp_float_t)%.16g, (mp_float_t)%.16g};"
                 % (obj_name, obj.real, obj.imag)
diff --git a/tools/mpy_ld.py b/tools/mpy_ld.py
index 87e57869f6..7f0fcbca22 100755
--- a/tools/mpy_ld.py
+++ b/tools/mpy_ld.py
@@ -232,34 +232,20 @@ def extract_qstrs(source_files):
     def read_qstrs(f):
         with open(f) as f:
             vals = set()
-            objs = set()
             for line in f:
-                while line:
-                    m = re.search(r"MP_OBJ_NEW_QSTR\((MP_QSTR_[A-Za-z0-9_]*)\)", line)
-                    if m:
-                        objs.add(m.group(1))
-                    else:
-                        m = re.search(r"MP_QSTR_[A-Za-z0-9_]*", line)
-                        if m:
-                            vals.add(m.group())
-                    if m:
-                        s = m.span()
-                        line = line[: s[0]] + line[s[1] :]
-                    else:
-                        line = ""
-            return vals, objs
+                for m in re.finditer(r"MP_QSTR_[A-Za-z0-9_]*", line):
+                    vals.add(m.group())
+            return vals
 
     static_qstrs = ["MP_QSTR_" + qstrutil.qstr_escape(q) for q in qstrutil.static_qstr_list]
 
     qstr_vals = set()
-    qstr_objs = set()
     for f in source_files:
-        vals, objs = read_qstrs(f)
+        vals = read_qstrs(f)
         qstr_vals.update(vals)
-        qstr_objs.update(objs)
     qstr_vals.difference_update(static_qstrs)
 
-    return static_qstrs, qstr_vals, qstr_objs
+    return static_qstrs, qstr_vals
 
 
 ################################################################################
@@ -730,7 +716,7 @@ def load_object_file(env, felf):
                 env.unresolved_syms.append(sym)
 
 
-def link_objects(env, native_qstr_vals_len, native_qstr_objs_len):
+def link_objects(env, native_qstr_vals_len):
     # Build GOT information
     if env.arch.name == "EM_XTENSA":
         build_got_xtensa(env)
@@ -761,7 +747,7 @@ def link_objects(env, native_qstr_vals_len, native_qstr_objs_len):
     # Create section to contain mp_native_obj_table
     env.obj_table_section = Section(
         ".external.obj_table",
-        bytearray(native_qstr_objs_len * env.arch.word_size),
+        bytearray(0 * env.arch.word_size),  # currently empty
         env.arch.word_size,
     )
 
@@ -899,7 +885,7 @@ class MPYOutput:
             self.write_uint(n)
 
 
-def build_mpy(env, entry_offset, fmpy, native_qstr_vals, native_qstr_objs):
+def build_mpy(env, entry_offset, fmpy, native_qstr_vals):
     # Write jump instruction to start of text
     jump = env.arch.asm_jump(entry_offset)
     env.full_text[: len(jump)] = jump
@@ -927,7 +913,7 @@ def build_mpy(env, entry_offset, fmpy, native_qstr_vals, native_qstr_objs):
     out.write_uint(1 + len(native_qstr_vals))
 
     # MPY: n_obj
-    out.write_uint(len(native_qstr_objs))
+    out.write_uint(0)
 
     # MPY: qstr table
     out.write_qstr(fmpy)  # filename
@@ -935,10 +921,7 @@ def build_mpy(env, entry_offset, fmpy, native_qstr_vals, native_qstr_objs):
         out.write_qstr(q)
 
     # MPY: object table
-    for q in native_qstr_objs:
-        out.write_bytes(bytearray([MP_PERSISTENT_OBJ_STR]))
-        out.write_uint(len(q))
-        out.write_bytes(bytes(q, "utf8") + b"\x00")
+    # <empty>
 
     # MPY: kind/len
     out.write_uint(len(env.full_text) << 3 | (MP_CODE_NATIVE_VIPER - MP_CODE_BYTECODE))
@@ -965,11 +948,15 @@ def build_mpy(env, entry_offset, fmpy, native_qstr_vals, native_qstr_objs):
         out.write_bytes(env.full_rodata)
 
     # MPY: relocation information
+    # See py/persistentcode.c:mp_native_relocate for meaning of the `kind` integer values.
     prev_kind = None
+    prev_base = None
+    prev_offset = None
+    prev_n = None
     for base, addr, kind in env.mpy_relocs:
         if isinstance(kind, str) and kind.startswith(".text"):
             kind = 0
-        elif kind in (".rodata", ".data.rel.ro"):
+        elif isinstance(kind, str) and kind.startswith((".rodata", ".data.rel.ro")):
             if env.arch.separate_rodata:
                 kind = rodata_const_table_idx
             else:
@@ -1013,7 +1000,7 @@ def do_preprocess(args):
     if args.output is None:
         assert args.files[0].endswith(".c")
         args.output = args.files[0][:-1] + "config.h"
-    static_qstrs, qstr_vals, qstr_objs = extract_qstrs(args.files)
+    static_qstrs, qstr_vals = extract_qstrs(args.files)
     with open(args.output, "w") as f:
         print(
             "#include <stdint.h>\n"
@@ -1026,11 +1013,6 @@ def do_preprocess(args):
             print("#define %s (%u)" % (q, i + 1), file=f)
         for i, q in enumerate(sorted(qstr_vals)):
             print("#define %s (mp_native_qstr_table[%d])" % (q, i + 1), file=f)
-        for i, q in enumerate(sorted(qstr_objs)):
-            print(
-                "#define MP_OBJ_NEW_QSTR_%s ((mp_obj_t)mp_native_obj_table[%d])" % (q, i),
-                file=f,
-            )
         print("extern const uint16_t mp_native_qstr_table[];", file=f)
         print("extern const mp_uint_t mp_native_obj_table[];", file=f)
 
@@ -1040,25 +1022,19 @@ def do_link(args):
         assert args.files[0].endswith(".o")
         args.output = args.files[0][:-1] + "mpy"
     native_qstr_vals = []
-    native_qstr_objs = []
     if args.qstrs is not None:
         with open(args.qstrs) as f:
             for l in f:
                 m = re.match(r"#define MP_QSTR_([A-Za-z0-9_]*) \(mp_native_", l)
                 if m:
                     native_qstr_vals.append(m.group(1))
-                else:
-                    m = re.match(r"#define MP_OBJ_NEW_QSTR_MP_QSTR_([A-Za-z0-9_]*)", l)
-                    if m:
-                        native_qstr_objs.append(m.group(1))
     log(LOG_LEVEL_2, "qstr vals: " + ", ".join(native_qstr_vals))
-    log(LOG_LEVEL_2, "qstr objs: " + ", ".join(native_qstr_objs))
     env = LinkEnv(args.arch)
     try:
         for file in args.files:
             load_object_file(env, file)
-        link_objects(env, len(native_qstr_vals), len(native_qstr_objs))
-        build_mpy(env, env.find_addr("mpy_init"), args.output, native_qstr_vals, native_qstr_objs)
+        link_objects(env, len(native_qstr_vals))
+        build_mpy(env, env.find_addr("mpy_init"), args.output, native_qstr_vals)
     except LinkError as er:
         print("LinkError:", er.args[0])
         sys.exit(1)