diff --git a/ports/stm32/boards/OPENMV2/board_init.c b/ports/stm32/boards/OPENMV2/board_init.c
new file mode 100644
index 000000000000..2bc1d187c062
--- /dev/null
+++ b/ports/stm32/boards/OPENMV2/board_init.c
@@ -0,0 +1,8 @@
+#include "py/mphal.h"
+#define OMV_BOOTLOADER_MAGIC_ADDR   (0x1000FFFCU)
+#define OMV_BOOTLOADER_MAGIC_VALUE  (0xB00710ADU)
+
+void board_enter_bootloader(void) {
+    *((uint32_t *) OMV_BOOTLOADER_MAGIC_ADDR) = OMV_BOOTLOADER_MAGIC_VALUE;
+    NVIC_SystemReset();
+}
diff --git a/ports/stm32/boards/OPENMV2/mpconfigboard.h b/ports/stm32/boards/OPENMV2/mpconfigboard.h
index 5d0b8f616dec..37d0708f413e 100644
--- a/ports/stm32/boards/OPENMV2/mpconfigboard.h
+++ b/ports/stm32/boards/OPENMV2/mpconfigboard.h
@@ -26,9 +26,10 @@ typedef unsigned int mp_uint_t;     // must be pointer size
 #define MICROPY_HW_ENABLE_USB       (1)
 #define MICROPY_HW_ENABLE_SDCARD    (1)
 #define MICROPY_HW_TIM_IS_RESERVED(id) (id == 1 || id == 6)
-
 #define MICROPY_HW_ENTER_BOOTLOADER_VIA_RESET   (0)
-#define MICROPY_BOARD_ENTER_BOOTLOADER(nargs, args) NVIC_SystemReset()
+
+extern void board_enter_bootloader(void);
+#define MICROPY_BOARD_ENTER_BOOTLOADER(nargs, args) board_enter_bootloader()
 
 #define MICROPY_HW_CLK_PLLM (6)
 #define MICROPY_HW_CLK_PLLN (360)
diff --git a/ports/stm32/boards/OPENMV3/board_init.c b/ports/stm32/boards/OPENMV3/board_init.c
new file mode 100644
index 000000000000..cc699644b5cc
--- /dev/null
+++ b/ports/stm32/boards/OPENMV3/board_init.c
@@ -0,0 +1,8 @@
+#include "py/mphal.h"
+#define OMV_BOOTLOADER_MAGIC_ADDR   (0x2001FFFCU)
+#define OMV_BOOTLOADER_MAGIC_VALUE  (0xB00710ADU)
+
+void board_enter_bootloader(void) {
+    *((uint32_t *) OMV_BOOTLOADER_MAGIC_ADDR) = OMV_BOOTLOADER_MAGIC_VALUE;
+    NVIC_SystemReset();
+}
diff --git a/ports/stm32/boards/OPENMV3/mpconfigboard.h b/ports/stm32/boards/OPENMV3/mpconfigboard.h
index 6adc57a3be63..389d8ec6a8e9 100644
--- a/ports/stm32/boards/OPENMV3/mpconfigboard.h
+++ b/ports/stm32/boards/OPENMV3/mpconfigboard.h
@@ -27,9 +27,10 @@ typedef unsigned int mp_uint_t;     // must be pointer size
 #define MICROPY_HW_ENABLE_USB       (1)
 #define MICROPY_HW_ENABLE_SDCARD    (1)
 #define MICROPY_HW_TIM_IS_RESERVED(id) (id == 1 || id == 6)
-
 #define MICROPY_HW_ENTER_BOOTLOADER_VIA_RESET   (0)
-#define MICROPY_BOARD_ENTER_BOOTLOADER(nargs, args) NVIC_SystemReset()
+
+extern void board_enter_bootloader(void);
+#define MICROPY_BOARD_ENTER_BOOTLOADER(nargs, args) board_enter_bootloader()
 
 #define MICROPY_HW_CLK_PLLM (12)
 #define MICROPY_HW_CLK_PLLN (432)
diff --git a/ports/stm32/boards/OPENMV4/board_init.c b/ports/stm32/boards/OPENMV4/board_init.c
new file mode 100644
index 000000000000..cc699644b5cc
--- /dev/null
+++ b/ports/stm32/boards/OPENMV4/board_init.c
@@ -0,0 +1,8 @@
+#include "py/mphal.h"
+#define OMV_BOOTLOADER_MAGIC_ADDR   (0x2001FFFCU)
+#define OMV_BOOTLOADER_MAGIC_VALUE  (0xB00710ADU)
+
+void board_enter_bootloader(void) {
+    *((uint32_t *) OMV_BOOTLOADER_MAGIC_ADDR) = OMV_BOOTLOADER_MAGIC_VALUE;
+    NVIC_SystemReset();
+}
diff --git a/ports/stm32/boards/OPENMV4/mpconfigboard.h b/ports/stm32/boards/OPENMV4/mpconfigboard.h
index 6fdfb9fcc6eb..464f65034f01 100644
--- a/ports/stm32/boards/OPENMV4/mpconfigboard.h
+++ b/ports/stm32/boards/OPENMV4/mpconfigboard.h
@@ -21,9 +21,10 @@ typedef unsigned int mp_uint_t;     // must be pointer size
 #define MICROPY_HW_ENABLE_USB       (1)
 #define MICROPY_HW_ENABLE_SDCARD    (1)
 #define MICROPY_HW_TIM_IS_RESERVED(id) (id == 1 || id == 6)
-
 #define MICROPY_HW_ENTER_BOOTLOADER_VIA_RESET   (0)
-#define MICROPY_BOARD_ENTER_BOOTLOADER(nargs, args) NVIC_SystemReset()
+
+extern void board_enter_bootloader(void);
+#define MICROPY_BOARD_ENTER_BOOTLOADER(nargs, args) board_enter_bootloader()
 
 // Note these are not used in top system.c.
 #define MICROPY_HW_CLK_PLLM         (3)
diff --git a/ports/stm32/boards/OPENMV4P/board_init.c b/ports/stm32/boards/OPENMV4P/board_init.c
index 7c599b4b2094..c0c5e9b68639 100644
--- a/ports/stm32/boards/OPENMV4P/board_init.c
+++ b/ports/stm32/boards/OPENMV4P/board_init.c
@@ -2,8 +2,10 @@
 #include "storage.h"
 #include "sdram.h"
 
-void board_low_power(int mode)
-{
+#define OMV_BOOTLOADER_MAGIC_ADDR   (0x2001FFFCU)
+#define OMV_BOOTLOADER_MAGIC_VALUE  (0xB00710ADU)
+
+void board_low_power(int mode) {
     switch (mode) {
         case 0:     // Leave stop mode.
             sdram_leave_low_power();
@@ -18,3 +20,8 @@ void board_low_power(int mode)
     // Enable QSPI deepsleep for modes 1 and 2
     mp_spiflash_deepsleep(&spi_bdev.spiflash, (mode != 0));
 }
+
+void board_enter_bootloader(void) {
+    *((uint32_t *) OMV_BOOTLOADER_MAGIC_ADDR) = OMV_BOOTLOADER_MAGIC_VALUE;
+    NVIC_SystemReset();
+}
diff --git a/ports/stm32/boards/OPENMV4P/mpconfigboard.h b/ports/stm32/boards/OPENMV4P/mpconfigboard.h
index c893840c9384..38c7d20624ec 100644
--- a/ports/stm32/boards/OPENMV4P/mpconfigboard.h
+++ b/ports/stm32/boards/OPENMV4P/mpconfigboard.h
@@ -21,9 +21,10 @@ typedef unsigned int mp_uint_t;     // must be pointer size
 #define MICROPY_HW_HAS_FLASH        (1)
 #define MICROPY_HW_ENABLE_SDCARD    (1)
 #define MICROPY_HW_TIM_IS_RESERVED(id) (id == 1 || id == 6)
-
 #define MICROPY_HW_ENTER_BOOTLOADER_VIA_RESET   (0)
-#define MICROPY_BOARD_ENTER_BOOTLOADER(nargs, args) NVIC_SystemReset()
+
+extern void board_enter_bootloader(void);
+#define MICROPY_BOARD_ENTER_BOOTLOADER(nargs, args) board_enter_bootloader()
 
 // Note these are not used in top system.c.
 #define MICROPY_HW_CLK_PLLM         (3)
diff --git a/ports/stm32/boards/OPENMVPT/board_init.c b/ports/stm32/boards/OPENMVPT/board_init.c
index 7c599b4b2094..c0c5e9b68639 100644
--- a/ports/stm32/boards/OPENMVPT/board_init.c
+++ b/ports/stm32/boards/OPENMVPT/board_init.c
@@ -2,8 +2,10 @@
 #include "storage.h"
 #include "sdram.h"
 
-void board_low_power(int mode)
-{
+#define OMV_BOOTLOADER_MAGIC_ADDR   (0x2001FFFCU)
+#define OMV_BOOTLOADER_MAGIC_VALUE  (0xB00710ADU)
+
+void board_low_power(int mode) {
     switch (mode) {
         case 0:     // Leave stop mode.
             sdram_leave_low_power();
@@ -18,3 +20,8 @@ void board_low_power(int mode)
     // Enable QSPI deepsleep for modes 1 and 2
     mp_spiflash_deepsleep(&spi_bdev.spiflash, (mode != 0));
 }
+
+void board_enter_bootloader(void) {
+    *((uint32_t *) OMV_BOOTLOADER_MAGIC_ADDR) = OMV_BOOTLOADER_MAGIC_VALUE;
+    NVIC_SystemReset();
+}
diff --git a/ports/stm32/boards/OPENMVPT/mpconfigboard.h b/ports/stm32/boards/OPENMVPT/mpconfigboard.h
index 8a868dfc1c11..797e92338780 100644
--- a/ports/stm32/boards/OPENMVPT/mpconfigboard.h
+++ b/ports/stm32/boards/OPENMVPT/mpconfigboard.h
@@ -21,9 +21,10 @@ typedef unsigned int mp_uint_t;     // must be pointer size
 #define MICROPY_HW_ENABLE_USB       (1)
 #define MICROPY_HW_ENABLE_SDCARD    (1)
 #define MICROPY_HW_TIM_IS_RESERVED(id) (id == 1 || id == 6)
-
 #define MICROPY_HW_ENTER_BOOTLOADER_VIA_RESET   (0)
-#define MICROPY_BOARD_ENTER_BOOTLOADER(nargs, args) NVIC_SystemReset()
+
+extern void board_enter_bootloader(void);
+#define MICROPY_BOARD_ENTER_BOOTLOADER(nargs, args) board_enter_bootloader()
 
 // Note these are not used in top system.c.
 #define MICROPY_HW_CLK_PLLM         (3)