diff --git a/ports/mimxrt/Makefile b/ports/mimxrt/Makefile
index 574aebb4cd..680e87cac4 100644
--- a/ports/mimxrt/Makefile
+++ b/ports/mimxrt/Makefile
@@ -125,7 +125,7 @@ LIBS = $(shell $(CC) $(CFLAGS) -print-libgcc-file-name)
 
 # Tune for Debugging or Optimization
 ifeq ($(DEBUG),1)
-CFLAGS += -O0 -ggdb
+CFLAGS += -Og -ggdb
 LDFLAGS += --gc-sections
 CFLAGS += -fdata-sections -ffunction-sections
 else
diff --git a/ports/mimxrt/hal/phy/device/phydp83848/fsl_phydp83848.c b/ports/mimxrt/hal/phy/device/phydp83848/fsl_phydp83848.c
index 0ef618d421..07ce6d1f7f 100644
--- a/ports/mimxrt/hal/phy/device/phydp83848/fsl_phydp83848.c
+++ b/ports/mimxrt/hal/phy/device/phydp83848/fsl_phydp83848.c
@@ -25,7 +25,7 @@
 #define PHY_PHYSTS_LINK_MASK          0x0001U /*!< The PHY link up mask. */
 
 #define PHY_RMII_MODE                 0x20
-#define PHY_RMII_REV1_0               0x10   
+#define PHY_RMII_REV1_0               0x10
 
 /*! @brief Defines the timeout macro. */
 #define PHY_READID_TIMEOUT_COUNT 1000U
diff --git a/ports/mimxrt/mimxrt_flash.c b/ports/mimxrt/mimxrt_flash.c
index 25a11ab7ca..27ab987ed1 100644
--- a/ports/mimxrt/mimxrt_flash.c
+++ b/ports/mimxrt/mimxrt_flash.c
@@ -79,7 +79,7 @@ status_t flash_erase_block(uint32_t erase_addr) {
 // the vfs driver takes care for erasing the sector if required
 status_t flash_write_block(uint32_t dest_addr, const uint8_t *src, uint32_t length) __attribute__((section(".ram_functions")));
 status_t flash_write_block(uint32_t dest_addr, const uint8_t *src, uint32_t length) {
-    status_t status;
+    status_t status = 0;
     uint32_t size;
     uint32_t next_addr;