Having bother connecting your flight controller (FC) to Betaflight configurator in your laptop, or flashing firmware? Normally, that is brought on by lacking or incorrect drivers, or unhealthy cable. On this tutorial, I’ll clarify the potential causes and easy step-by-step options that can assist you repair the difficulty. I’ll additionally cowl the fundamentals of the drivers wanted for STM32-based flight controllers, so that you perceive what you’re doing.
New to FPV? Be taught the fundamentals of flight controllers in my purchaser’s information: https://oscarliang.com/flight-controller/
You Want Two Drivers
Betaflight flight controllers require two major drivers: the VCP driver and the DFU driver. Right here’s what every does:
VCP Driver (Digital COM Port)
- Used when your flight controller is in regular working mode — this permits Betaflight Configurator to attach, learn, and write settings.
- When it’s working correctly, Betaflight Configurator will acknowledge the FC as a COM port, e.g.
COM3. - Home windows normally installs this driver mechanically, so for many customers, it must be plug and play.
DFU Driver (Gadget Firmware Improve)
- Used when your flight controller is in bootloader mode — that is the mode required for flashing firmware.
- On this mode, the FC reveals up in Home windows as “
STM32 BOOTLOADER”, and in Betaflight Configurator as “DFU”. - Newbies typically wrestle with DFU mode as a result of it requires manually placing the FC into bootloader mode and putting in the DFU driver
- You might also need to repeat this course of for various flight controllers, so anticipate to come across DFU driver points once you get a brand new drone. However when you perceive the method and the widespread causes, although, it turns into simple to deal with.
Learn to enter DFU mode right here: https://oscarliang.com/dfu-mode/
Didn’t Open Serial Port
The error “Didn't open serial port” is likely one of the commonest points when connecting a flight controller to Betaflight Configurator.
Frequent Causes and Options
- One other software program is utilizing the COM port (e.g., BLHeli Configurator, INAV, or a serial terminal). Attempt closing all of the apps, even your browser, something that could be accessing the FC. Generally Home windows locks the port, so attempt unplugging and replugging the USB cable to reset it. If that doesn’t work, restart your PC. Nonetheless no luck? Attempt a special PC to rule out software program points.
- Attempt a special USB cable, ensure that it’s a knowledge cable, not charge-only. Be sure that the connector is firmly inserted on each ends.
- Lacking or incorrect VCP driver. That is much less widespread, however can occur in case your STM32 VCP driver isn’t correctly put in.
- Open Gadget Supervisor → Ports (COM & LPT). You must see one thing like:
STM32 Digital COM Port (COM3). - If you happen to see “Unknown Gadget” or “USB Serial Gadget”, you doubtless want to put in the VCP driver. To repair it, there are 3 strategies you possibly can attempt:
- Obtain and run the ImpulseRC Driver Fixer instrument right here, that is the best method.
- Or set up the Digital COM Port (VCP) Driver from ST: https://www.st.com/en/development-tools/stsw-stm32102.html. You’ll must create a login or present your e-mail deal with to obtain the obtain hyperlink.
- Alternatively, attempt the official CP210x USB to UART Bridge Digital COM Port driver right here.
- Open Gadget Supervisor → Ports (COM & LPT). You must see one thing like:
Can’t Get Into Bootloader Mode (DFU)
To flash firmware, your flight controller (FC) must be in bootloader mode, often known as DFU mode.
Most flight controllers have a boot button. Maintain down this button whereas plugging within the USB cable, and the FC ought to enter DFU mode. There are additionally different strategies to enter DFU mode (for instance, by Betaflight CLI instructions). I’ve defined all of them intimately right here — I gained’t repeat them on this publish to maintain it brief: https://oscarliang.com/dfu-mode/
If you happen to can’t get into DFU mode, the best repair is to make use of the ImpulseRC Driver Fixer instrument.
- Join your flight controller to your laptop by way of USB.
- Obtain and run the ImpulseRC Driver Fixer instrument right here.
- The instrument will mechanically detect your flight controller and set up the right drivers. If it retains saying “Looking for flight controller”, attempt unplug FC and plug it again in with out urgent the bootloader button.
As soon as it’s achieved, open Betaflight Configurator — your FC ought to now seem in DFU mode.
Nonetheless Can’t Get Into DFU Mode: Disconnect UART!
If you happen to can’t get into DFU mode, otherwise you get an error “Surprising Variety of Units Detected” whereas utilizing ImpulseRC Driver Fixer, it could possibly be brought on by different parts related to your FC which might be interfering. This contains units like: receiver, GPS module, DJI Air Unit and so on. Mainly something that’s related to the serial ports / UART’s.
Resolution: Disconnect all peripherals, depart solely the USB cable plugged in, and run the instrument once more.
Fallacious DFU Driver Put in
In case your FC connects to Betaflight Configurator simply high quality, however when making an attempt to flash firmware, it offers you the “Didn’t open serial port” error and ImpulseRC Driver Fixer doesn’t resolve the difficulty, it’s attainable that the incorrect DFU driver is put in. In my case, it was “Guillemot STM DFU Gadget“, however the appropriate DFU driver must be “STM32 BOOTLOADER“.
Methods to Test
- Put your FC in DFU mode.
- Open Gadget Supervisor and search for “Guillemot STM DFU Gadget” underneath any class (typically underneath Sound, Video and Sport Controllers).
- If you happen to see it — congratulations, you’ve discovered the issue! That’s the incorrect driver.
Why Reinstalling the Driver Doesn’t Work
Merely reinstalling the motive force utilizing Zadig or ImpulseRC Driver Fixer would possibly seem to work at first — the machine could briefly present up as “STM32 BOOTLOADER” — however it’ll all the time revert again to “Guillemot STM DFU Gadget.”
It’s because the Guillemot driver mechanically reinstalls itself except it’s fully eliminated out of your system.
Methods to Repair It (Utterly Take away Guillemot)
- Delete these two folders in the event that they exist:
C:Program FilesGuillemotC:Program Recordsdata (x86)Guillemot
- Along with your FC related in DFU mode, open Gadget Supervisor, discover
Guillemot STM DFU Gadget, right-click it → Uninstall machine, and verify “Delete the motive force software program for this machine.” - Unplug the FC and reboot your laptop.
- Put your FC again into bootloader mode and run ImpulseRC Driver Fixer once more.
You must now have the ability to flash firmware efficiently.
Nothing Works?
I’ve personally had a pc that would connect with Betaflight Configurator simply high quality — however by no means managed to flash firmware, it doesn’t matter what I attempted.
Totally different cables, totally different drivers, countless troubleshooting — nothing labored after making an attempt for months.
In case you have a cussed laptop like that, there’s the work round: Use the Speedybee app in your smartphone. You may connect with your FC, change settings, and flash firmware similar to the desktop Betaflight Configurator.
AT32 Flight Controllers
If you first plug an AT32 flight controller into your PC, Home windows usually installs the drivers mechanically, and Betaflight ought to have the ability to connect with it after a couple of seconds. Within the COM Port it ought to present “AT32 Digital COM Port”. If this isn’t the case, you possibly can obtain and set up the drivers manually:
- Go to the MCU web page: https://www.arterychip.com/en/product/AT32F435.jsp
- Within the “USB Instrument and Driver” part , obtain “Digital serial port composite PC driver”: https://www.arterychip.com/obtain/USB_Tool_Driver/VirtualCOM_Composite_DriverInstalll_V1.0.31.zip
AT32 FC additionally requires totally different DFU drivers. Once more this could be put in mechanically but when not you are able to do it manually.
- Go to the web page of the microcontroller involved, due to this fact the AT32F435: https://www.arterychip.com/en/product/AT32F435.jsp
- In Assets, then “Instrument” on the backside of the web page, obtain “In-System-Programming instrument supporting AT32 MCU”: https://www.arterychip.com/obtain/TOOL/Artery_ISP_Programmer_V2.0.11.zip
- Unzip and enter the “Artery_DFU_DriverInstall” listing to launch the installer. Begin the set up then restart the PC
Notice: the ImpulseRC Driver Fixer doesn’t work for FC with AT32 processor, solely STM32 ones.
Methods to Set up Driver On MacOS
Driver set up on macOS is barely totally different.
- Obtain and set up the CP210x driver for macOS.
- Throughout set up, macOS could block it as a result of it’s from an unauthorized developer.
- Go to System Preferences → Safety & Privateness.
- Click on the padlock icon to unlock settings.
- Click on “Allow” or “Enable” subsequent to SiLabs.
- Restart your Mac.
- As soon as put in, you might want to return to the identical place to permit unauthorised utility, Silabs on this case.
FAQ
Q: I’m having bother flashing the board. DFU mode reveals up in Betaflight Configurator, however flashing fails with this message: “Learn safety not energetic. USB machine efficiently closed.”
A: Attempt unchecking the “Full chip erase” choice earlier than flashing. After the firmware is put in, you possibly can reset your settings in CLI by typing: “default” in CLI to reset all settings.
Conclusion
Driver points are some of the widespread frustrations when organising a brand new drone or flight controller, particularly throughout totally different MCU sorts. With the right VCP and DFU drivers put in, Betaflight Configurator ought to join and flash firmware reliably in your PC. And there are all the time work round in case your PC fails you.
Edit Historical past
- Jul 2017 – Article created
- Aug 2017 – Added repair for lacking VCP driver
- Feb 2023 – Added repair for changing Guillemot DFU driver with STM32
- Sep 2024 – Added repair relating to macOS
- Feb 2025 – Added directions for putting in drivers for AT32 flight controllers
- Nov 2025 – Rewrote tutorial for readability and added extra detailed directions
