Fix Flight Controller Driver Issues – Can’t Connect or Flash Firmware

Having trouble connecting your FC to a computer, or flashing FC firmware? Very often it’s an issue with flight controller driver. This tutorial hopefully can 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.

The first thing you should do is to try a different USB cable. Sometimes an USB cable might be designed for charging and not for data connection, or the cable is simply damaged.

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:

  • CP2102
  • VCP

You can find out whether your FC is the CP2102 or VCP in order to choose the suitable solution to fix your driver issue.

VCP Boards: 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.

CP2102 Driver Fix

If you have a flight controller with CP2102, you need to install the CP2102 driver.

Note that with SPRF3 boards, you might want to try changing the baud rate to 256000 first, maybe that would do the trick.

First of all, connect your FC to the computer via USB. Without proper driver it’s difficult to tell where it is in Device Manager. The easiest thing to do is to use Zadigto find it.

You can download both the CP2102 and Zadig drivers on the front page of the Betaflight Configurator.

Run Zadig, choose your flight controller in the drop down list (1). There are going to be many options but choose the one that is more likely to be your FC.

After the green arrow select WinUSB (2), and press replace driver (3).

After that you should find the “CP2102 USB to UART Bridge Controller” under “Universal Serial Bus devices”. The one that isn’t greyed out. Right click on it and click Update Driver Software.

Select the driver you want to install, Silicon Labs, CP210x USB to UART Bridge.

And that’s it, the COM port of your FC should now appear in the FC configurator.


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

16 thoughts on “Fix Flight Controller Driver Issues – Can’t Connect or Flash Firmware

  1. Rob

    Has anyone seen the DFU mode open the USB port and close it without installing the firmware?

    The INAV message log is

    2019-10-11 @ 12:54:04 — USB device successfully opened with ID: 1
    2019-10-11 @ 12:54:04 — USB device successfully closed

    So nothing happens!!
    File is
    I believe all the drivers are correct,
    The STM32 BOOTLOADER shows on the Device Manager (Windows 10)

    I can connect to the FC via the Com port as usual.
    The FC is the new Matek F765 Wing.

    I want to flash ardupilot.

  2. Vidyadhar Patil

    My flight controller diatone mamba f405 is not showing any sensor on board after I flashed the firmware with STM32F405 firmware. What could be the problem?

  3. Andrés Giraldo

    My Diatone GT M3 V2 won’t connect to Betaflight or let me flash the firmware. When I connect the battery it beeps 3 times only, not 5 as it should. Please, I’ve been looking for an answer to this for hours and hours.The FC appears to work because it has its green light on, steady. I use a Mac laptop so I don’t think is a matter of drivers. Please give some some advice to fix this. Thank you!!

  4. Kyle

    So I’m having an issue I’ve never seen and cannot seem to find a solution. My FC shows up fine at com5, and I can start the connection. It just says connecting for a moment, saying successfully serial port successfuly opened then changes to successfully closed. Everything is brand new, this is a first time setup on this quad.

  5. Daniel

    Thank you very much for this tutorial, I had been looking for a solution to my problem for a long time.
    I have a dys f4 pro v2

    Greetings from Spain

  6. Mark

    My FC won’t connect after a hard impact that broke the nylon standoffs. When I plug it into USB all windows does is make the ‘usb connection’ sound over and over. I can connect with my other quads. Is the FC cooked? The original 4 in 1esc is good and being used, but I wanted to try and salvage the FC if possible. I’ve even tried shorting the boot pins but nothing.

  7. Andrew

    I have tried using Zdaig and when I try and replace the USB drivers I get the error:

    Drivers already installed.

  8. Tyler Walker

    My spf3 wont talk to computer anymore after flashing. My other quads all still connect fine. Is my usb on fc cooked??

  9. Steve

    Hi, I’ve done all this, when I plug the FC board into my computer with a good cable windows recognizes it, but none of the configurators will show it.

    What am I doing wrong?

  10. 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?

  11. 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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