diff --git a/scripts/flash_usb.py b/scripts/flash_usb.py
index 4fc72716..bb1afcce 100755
--- a/scripts/flash_usb.py
+++ b/scripts/flash_usb.py
@@ -189,7 +189,11 @@ def flash_stm32f1(options, binfile):
         sys.exit(-1)
 
 STM32F4_HELP = """
-USB flash is not supported on the STM32F4!
+Failed to flash to %s: %s
+
+If the device is already in bootloader mode it can be flashed with the
+following command:
+  make flash FLASH_DEVICE=0483:df11
 
 If attempting to flash via 3.3V serial, then use:
   make serialflash FLASH_DEVICE=%s
@@ -197,8 +201,13 @@ If attempting to flash via 3.3V serial, then use:
 """
 
 def flash_stm32f4(options, binfile):
-    sys.stderr.write(STM32F4_HELP % (options.device,))
-    sys.exit(-1)
+    try:
+        flash_dfuutil(options.device, binfile,
+                      ["-R", "-a", "0", "-s", str(options.start)], options.sudo)
+    except error as e:
+        sys.stderr.write(STM32F4_HELP % (
+            options.device, str(e), options.device))
+        sys.exit(-1)
 
 MCUTYPES = {
     'atsam3': flash_atsam3, 'atsam4': flash_atsam4, 'atsamd': flash_atsamd,
@@ -219,6 +228,8 @@ def main():
                     help="serial port device")
     opts.add_option("-o", "--offset", type="string", dest="offset",
                     help="flash offset")
+    opts.add_option("-s", "--start", type="int", dest="start",
+                    help="start address in flash")
     opts.add_option("--no-sudo", action="store_false", dest="sudo",
                     default=True, help="do not run sudo")
     options, args = opts.parse_args()
diff --git a/src/stm32/Makefile b/src/stm32/Makefile
index c607328b..3ff257a7 100644
--- a/src/stm32/Makefile
+++ b/src/stm32/Makefile
@@ -54,7 +54,7 @@ FLASH_TYPE-$(CONFIG_MACH_STM32F4) := stm32f4
 
 flash: $(OUT)klipper.bin
 	@echo "  Flashing $< to $(FLASH_DEVICE)"
-	$(Q)$(PYTHON) ./scripts/flash_usb.py -t $(FLASH_TYPE-y) -d "$(FLASH_DEVICE)" $(if $(NOSUDO),--no-sudo) $(OUT)klipper.bin
+	$(Q)$(PYTHON) ./scripts/flash_usb.py -t $(FLASH_TYPE-y) -d "$(FLASH_DEVICE)" -s "$(CONFIG_FLASH_START)" $(if $(NOSUDO),--no-sudo) $(OUT)klipper.bin
 
 serialflash: $(OUT)klipper.bin
 	@echo "  Flashing $< to $(FLASH_DEVICE) via stm32flash"
diff --git a/src/stm32/stm32f4.c b/src/stm32/stm32f4.c
index e1f22b2f..92c40b22 100644
--- a/src/stm32/stm32f4.c
+++ b/src/stm32/stm32f4.c
@@ -6,6 +6,7 @@
 
 #include "autoconf.h" // CONFIG_CLOCK_REF_8M
 #include "board/armcm_boot.h" // VectorTable
+#include "board/irq.h" // irq_disable
 #include "board/usb_cdc.h" // usb_request_bootloader
 #include "command.h" // DECL_CONSTANT_STR
 #include "internal.h" // enable_pclock
@@ -88,10 +89,16 @@ gpio_peripheral(uint32_t gpio, uint32_t mode, int pullup)
     regs->OSPEEDR = (regs->OSPEEDR & ~m_msk) | (0x02 << m_shift);
 }
 
+#define USB_BOOT_FLAG_ADDR (CONFIG_RAM_START + CONFIG_RAM_SIZE - 4096)
+#define USB_BOOT_FLAG 0x55534220424f4f54 // "USB BOOT"
+
 // Handle USB reboot requests
 void
 usb_request_bootloader(void)
 {
+    irq_disable();
+    *(uint64_t*)USB_BOOT_FLAG_ADDR = USB_BOOT_FLAG;
+    NVIC_SystemReset();
 }
 
 #if CONFIG_CLOCK_REF_8M
@@ -202,6 +209,13 @@ clock_setup(void)
 void
 armcm_main(void)
 {
+    if (*(uint64_t*)USB_BOOT_FLAG_ADDR == USB_BOOT_FLAG) {
+        *(uint64_t*)USB_BOOT_FLAG_ADDR = 0;
+        uint32_t *sysbase = (uint32_t*)0x1fff0000;
+        asm volatile("mov sp, %r0\n bx %r1"
+                     : : "r"(sysbase[0]), "r"(sysbase[1]));
+    }
+
     // Run SystemInit() and then restore VTOR
     SystemInit();
     SCB->VTOR = (uint32_t)VectorTable;