diff --git a/ports/esp32/boards/ESP32_GENERIC/sdkconfig.d2wd b/ports/esp32/boards/ESP32_GENERIC/sdkconfig.d2wd
index 7b4313b7de..f6e07893e9 100644
--- a/ports/esp32/boards/ESP32_GENERIC/sdkconfig.d2wd
+++ b/ports/esp32/boards/ESP32_GENERIC/sdkconfig.d2wd
@@ -3,6 +3,9 @@ CONFIG_COMPILER_OPTIMIZATION_SIZE=y
 CONFIG_COMPILER_OPTIMIZATION_PERF=n
 CONFIG_COMPILER_OPTIMIZATION_CHECKS_SILENT=y
 
+# Disable SPI Ethernet driver to reduce firmware size.
+CONFIG_ETH_USE_SPI_ETHERNET=n
+
 CONFIG_ESPTOOLPY_FLASHMODE_DIO=y
 CONFIG_ESPTOOLPY_FLASHFREQ_40M=y
 CONFIG_ESPTOOLPY_FLASHSIZE_2MB=y
diff --git a/ports/esp32/boards/ESP32_GENERIC/sdkconfig.ota b/ports/esp32/boards/ESP32_GENERIC/sdkconfig.ota
index e3a1f81fd3..352dd96f23 100644
--- a/ports/esp32/boards/ESP32_GENERIC/sdkconfig.ota
+++ b/ports/esp32/boards/ESP32_GENERIC/sdkconfig.ota
@@ -2,4 +2,6 @@ CONFIG_PARTITION_TABLE_CUSTOM=y
 CONFIG_PARTITION_TABLE_CUSTOM_FILENAME="partitions-4MiB-ota.csv"
 
 # Reduce firmware size to fit in the OTA partition.
+CONFIG_COMPILER_OPTIMIZATION_SIZE=y
+CONFIG_COMPILER_OPTIMIZATION_PERF=n
 CONFIG_COMPILER_OPTIMIZATION_CHECKS_SILENT=y