diff --git a/flashstub/stm32f4.c b/flashstub/stm32f4.c
index 6732897..1af271a 100644
--- a/flashstub/stm32f4.c
+++ b/flashstub/stm32f4.c
@@ -28,6 +28,7 @@ stm32f4_flash_write_stub(uint32_t *dest, uint32_t *src, uint32_t size)
 	for (int i = 0; i < size; i += 4) {
 		FLASH_CR = FLASH_CR_PROGRAM_X32 | FLASH_CR_PG;
 		*dest++ = *src++;
+		__asm("dsb");
 		while (FLASH_SR & FLASH_SR_BSY)
 			;
 	}
diff --git a/flashstub/stm32f4.stub b/flashstub/stm32f4.stub
index bd20406..b8fc412 100644
--- a/flashstub/stm32f4.stub
+++ b/flashstub/stm32f4.stub
@@ -1 +1 @@
-0x2300, 0x4C09, 0x4293, 0xD209, 0x4D08, 0x4E09, 0x602E, 0x58CD, 0x50C5, 0x6825, 0x03ED, 0xD4FC, 0x3304, 0xE7F2, 0x23F2, 0x6822, 0x421A, 0xD000, 0xBE01, 0xBE00, 0x3C0C, 0x4002, 0x3C10, 0x4002, 0x0201, 0x0000,
\ No newline at end of file
+0x2300, 0x4C0A, 0x4293, 0xD20B, 0x4E09, 0x4D0A, 0x602E, 0x58CD, 0x50C5, 0xF3BF, 0x8F4F, 0x6825, 0x03ED, 0xD4FC, 0x3304, 0xE7F0, 0x23F2, 0x6822, 0x421A, 0xD000, 0xBE01, 0xBE00, 0x3C0C, 0x4002, 0x0201, 0x0000, 0x3C10, 0x4002,
\ No newline at end of file