Solution to flight controller driver issues when flashing firmware

Are you having trouble flashing FC firmware? Most of the times, it could be a FC driver issue and this guide might help you fix it in a few simple steps.

Errors when flashing FC firmware

Often when there is a driver issue with the flight controller in Windows, you might get errors when press the button “Flash Firmware”. One common error is:

Failed to open serial port

Then the FC COM disappears, and it appears again when you unplug the FC and plug it back in… The same problem keeps happening when you try to flash the FC.

Or you might be getting this error:

No response from bootloader, programming failed

If you are able to connect your flight controller to Betaflight GUI, but you just cannot flash firmware. In which case please follow these steps to resolve the problem.

If you cannot connect to GUI at all, please try the “bootloader fix” first to flash the firmware. If that doesn’t help then read on.

Try restarting your computer and repeat the above before moving on.

2 types of flight controller driver issues

There are two types of flight controllers by the way they connect to a computer:

  • Older boards like the Seriously Pro Racer F3 (SPRF3) or Naze32 have a CP2102 chip on board which is used for configuration and flashing
  • Modern FC’s uses VCP (Virtual COM Port) and DFU modes to configure and flash firmware

It’s important you know which one your FC uses in order to choose which solution to fix your driver issue.

In the product specification it should tell you if your FC uses VCP or not. It’s a great bonus as it means your USB connection is not shared with UART1 and it’s usually listed as a feature. You can also find out in the Port tab in Betaflight Configurator, if it’s using VCP for connection then you should see “USB VCP” above the UART ports.

If you happen to have a flight controller with CP2102 (non-VCP), then google how to install CP2102 driver. Note that with SPRF3 boards the baud rate needs to be set to 256000.

The following fix is for VCP boards.

Fix FC driver issues using ImpulseRC Driver Tool

Connect your FC to the computer with USB cable.

Download and run ImpulseRC Driver Fixer Tool (it’s a 3rd party software, please scan with AV software before running it)

This tool will automatically search for your FC, and install whatever driver you need on your computer.

Once that’s completed successfully, the driver should be installed. Now fire up Betaflight Chrome App GUI, and you should see “DFU” next to the connect button, rather than the usual COM port in the text box.

You should now be able to flash the FC as you normally would.

Once done, your COM port will reappear in the text box. And you should be able to flash the FC from now on without any issues on this computer.


I am having problem flashing the board, I’ve tried everything, and DFU is displayed in GUI COM port, but it’s just not flashing and i get the following message:

Read protection not active. USB device successfully closed

Try to un-select “Full chip erase” option before flashing, and you could “erase settings” in CLI after the firmware flashing. Type “Default” in CLI to reset all settings.

Edit History

  • Jul 2017 – Article created
  • Aug 2017 – added fix for CP2102 missing driver

4 thoughts on “Solution to flight controller driver issues when flashing firmware

  1. paul

    I’m using impulse RC and I instaled before a lot of usb drivers. Now when I simply want to connect another FC board, there’s the “failed to open serial port” . I’m using Impulse RC at every connections with new FC board and it works! Is it normal to use it every time? Conflict with USB?

  2. DavidPi

    Might be worth mentioning that if COM port doesn’t show up after flashing the FW, you might need to install the STM32 VCP drivers.
    Another thing that I’ve experienced is conflicts in COM ports with other USB-to-serial drivers (Prolific, FTDI, etc.) so it might be worth removing those if you’re having trouble.


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