diff --git a/ports/stm32/boardctrl.c b/ports/stm32/boardctrl.c
index 922f218e92..02a3759991 100644
--- a/ports/stm32/boardctrl.c
+++ b/ports/stm32/boardctrl.c
@@ -25,9 +25,11 @@
  */
 
 #include "py/runtime.h"
+#include "py/objstr.h"
 #include "py/mphal.h"
 #include "shared/runtime/pyexec.h"
 #include "boardctrl.h"
+#include "powerctrl.h"
 #include "led.h"
 #include "usrsw.h"
 
@@ -43,6 +45,26 @@ STATIC void flash_error(int n) {
     led_state(PYB_LED_GREEN, 0);
 }
 
+#if MICROPY_HW_USES_BOOTLOADER
+void boardctrl_maybe_enter_mboot(size_t n_args, const void *args_in) {
+    const mp_obj_t *args = args_in;
+
+    if (n_args == 0 || !mp_obj_is_true(args[0])) {
+        // By default, with no args given, we enter the custom bootloader (mboot)
+        powerctrl_enter_bootloader(0x70ad0000, MBOOT_VTOR);
+    }
+
+    if (n_args == 1 && mp_obj_is_str_or_bytes(args[0])) {
+        // With a string/bytes given, pass its data to the custom bootloader
+        size_t len;
+        const char *data = mp_obj_str_get_data(args[0], &len);
+        void *mboot_region = (void *)*((volatile uint32_t *)MBOOT_VTOR);
+        memmove(mboot_region, data, len);
+        powerctrl_enter_bootloader(0x70ad0080, MBOOT_VTOR);
+    }
+}
+#endif
+
 #if !MICROPY_HW_USES_BOOTLOADER
 STATIC uint update_reset_mode(uint reset_mode) {
     #if MICROPY_HW_HAS_SWITCH
diff --git a/ports/stm32/boardctrl.h b/ports/stm32/boardctrl.h
index bc901f1c37..afd4ab8510 100644
--- a/ports/stm32/boardctrl.h
+++ b/ports/stm32/boardctrl.h
@@ -38,8 +38,12 @@
 #endif
 
 #ifndef MICROPY_BOARD_ENTER_BOOTLOADER
+#if MICROPY_HW_USES_BOOTLOADER
+#define MICROPY_BOARD_ENTER_BOOTLOADER(nargs, args) boardctrl_maybe_enter_mboot(nargs, args)
+#else
 #define MICROPY_BOARD_ENTER_BOOTLOADER(nargs, args)
 #endif
+#endif
 
 #ifndef MICROPY_BOARD_EARLY_INIT
 #define MICROPY_BOARD_EARLY_INIT()
@@ -106,6 +110,7 @@ typedef struct _boardctrl_state_t {
     bool log_soft_reset;
 } boardctrl_state_t;
 
+void boardctrl_maybe_enter_mboot(size_t n_args, const void *args);
 void boardctrl_before_soft_reset_loop(boardctrl_state_t *state);
 void boardctrl_top_soft_reset_loop(boardctrl_state_t *state);
 int boardctrl_run_boot_py(boardctrl_state_t *state);
diff --git a/ports/stm32/modmachine.c b/ports/stm32/modmachine.c
index 91061a3109..34e78d2616 100644
--- a/ports/stm32/modmachine.c
+++ b/ports/stm32/modmachine.c
@@ -30,7 +30,6 @@
 #include "modmachine.h"
 #include "py/gc.h"
 #include "py/runtime.h"
-#include "py/objstr.h"
 #include "py/mperrno.h"
 #include "py/mphal.h"
 #include "extmod/machine_bitstream.h"
@@ -283,22 +282,6 @@ NORETURN mp_obj_t machine_bootloader(size_t n_args, const mp_obj_t *args) {
 
     MICROPY_BOARD_ENTER_BOOTLOADER(n_args, args);
 
-    #if MICROPY_HW_USES_BOOTLOADER
-    if (n_args == 0 || !mp_obj_is_true(args[0])) {
-        // By default, with no args given, we enter the custom bootloader (mboot)
-        powerctrl_enter_bootloader(0x70ad0000, MBOOT_VTOR);
-    }
-
-    if (n_args == 1 && mp_obj_is_str_or_bytes(args[0])) {
-        // With a string/bytes given, pass its data to the custom bootloader
-        size_t len;
-        const char *data = mp_obj_str_get_data(args[0], &len);
-        void *mboot_region = (void *)*((volatile uint32_t *)MBOOT_VTOR);
-        memmove(mboot_region, data, len);
-        powerctrl_enter_bootloader(0x70ad0080, MBOOT_VTOR);
-    }
-    #endif
-
     #if defined(STM32F7) || defined(STM32H7)
     powerctrl_enter_bootloader(0, 0x1ff00000);
     #else