diff --git a/ports/stm32/boardctrl.h b/ports/stm32/boardctrl.h
index 6f79dfb890..f1cbc3b955 100644
--- a/ports/stm32/boardctrl.h
+++ b/ports/stm32/boardctrl.h
@@ -28,6 +28,10 @@
 
 #include "py/mpconfig.h"
 
+#ifndef MICROPY_BOARD_STARTUP
+#define MICROPY_BOARD_STARTUP powerctrl_check_enter_bootloader
+#endif
+
 #ifndef MICROPY_BOARD_EARLY_INIT
 #define MICROPY_BOARD_EARLY_INIT()
 #endif
diff --git a/ports/stm32/main.c b/ports/stm32/main.c
index bdf7328f68..888b20513c 100644
--- a/ports/stm32/main.c
+++ b/ports/stm32/main.c
@@ -313,8 +313,9 @@ void stm32_main(uint32_t reset_mode) {
     // Enable 8-byte stack alignment for IRQ handlers, in accord with EABI
     SCB->CCR |= SCB_CCR_STKALIGN_Msk;
 
-    // Check if bootloader should be entered instead of main application
-    powerctrl_check_enter_bootloader();
+    // Hook for a board to run code at start up, for example check if a
+    // bootloader should be entered instead of the main application.
+    MICROPY_BOARD_STARTUP();
 
     // Enable caches and prefetch buffers