message: ensure proper reset after DFU
diff: @@ -108,6 +108,14 @@ int main(void)
  jump_to_builtin_bootloader();
  }
  + /* The bootloader might fail to properly clean up after itself,
  + so if we're not sure that the system is in a clean state we
  + just reset it again */
  + if(*((unsigned long *)0x2001C000) != 42) {
  + *((unsigned long *)0x2001C000) = 42;
  + NVIC_SystemReset();
  + }
  +
  // This procedure of building a USB serial number should be identical
  // to the way the STM's built-in USB bootloader does it. This means
  // that the device will have the same serial number in normal and DFU mode.
  