Having hassle connecting your flight controller (FC) to Betaflight configurator in your laptop, or flashing firmware? Generally, that is attributable to 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 problem. 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 fundamental 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 enables 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 exhibits up in Home windows as “
STM32 BOOTLOADER”, and in Betaflight Configurator as “DFU”. - Learners usually 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 count on to come across DFU driver points once you get a brand new drone. However when you perceive the method and the frequent causes, although, it turns into simple to deal with.
Discover ways to enter DFU mode right here: https://oscarliang.com/dfu-mode/
Didn’t Open Serial Port
The error “Didn't open serial port” is without doubt one of the commonest points when connecting a flight controller to Betaflight Configurator.
Widespread Causes and Options
- One other software program is utilizing the COM port (e.g., BLHeli Configurator, INAV, or a serial terminal). Strive closing all of the apps, even your browser, something that is likely to be accessing the FC. Typically Home windows locks the port, so strive unplugging and replugging the USB cable to reset it. If that doesn’t work, restart your PC. Nonetheless no luck? Strive a unique PC to rule out software program points.
- Strive a unique USB cable, be certain that it’s an information cable, not charge-only. Be sure the connector is firmly inserted on each ends.
- Lacking or incorrect VCP driver. That is much less frequent, however can occur in case your STM32 VCP driver isn’t correctly put in.
- Open Gadget Supervisor → Ports (COM & LPT). You need to see one thing like:
STM32 Digital COM Port (COM3). - For those who see “Unknown Gadget” or “USB Serial Gadget”, you possible want to put in the VCP driver. To repair it, obtain and run the ImpulseRC Driver Fixer instrument right here, that ought to repair it. Alternatively, set up the official CP210x USB to UART Bridge Digital COM Port driver right here.
- Open Gadget Supervisor → Ports (COM & LPT). You need to 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, via Betaflight CLI instructions). I’ve defined all of them intimately right here — I gained’t repeat them on this submit to maintain it quick: https://oscarliang.com/dfu-mode/
For those who can’t get into DFU mode, the simplest 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 “Trying to find flight controller”, strive unplug FC and plug it again in with out urgent the bootloader button.
As soon as it’s accomplished, open Betaflight Configurator — your FC ought to now seem in DFU mode.
Error: “Sudden Variety of Units Detected”
For those who see this error whereas utilizing ImpulseRC Driver Fixer, it’s normally as a result of different elements related to your FC are interfering. This consists of units like: receiver, GPS module, DJI Air Unit and many others. Principally 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.
Unsuitable DFU Driver Put in
In case your FC connects to Betaflight Configurator simply high quality, however when attempting to flash firmware, it offers you the “Didn’t open serial port” error and ImpulseRC Driver Fixer doesn’t resolve the problem, it’s doable 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“.
The best way to Verify
- Put your FC in DFU mode.
- Open Gadget Supervisor and search for “Guillemot STM DFU Gadget” underneath any class (usually underneath Sound, Video and Sport Controllers).
- For those who see it — congratulations, you’ve discovered the issue! That’s the incorrect driver.
Why Reinstalling the Driver Doesn’t Work
Merely reinstalling the driving force utilizing Zadig or ImpulseRC Driver Fixer would possibly seem to work at first — the system might briefly present up as “STM32 BOOTLOADER” — however it is going to at all times revert again to “Guillemot STM DFU Gadget.”
It’s because the Guillemot driver mechanically reinstalls itself except it’s utterly eliminated out of your system.
The best way to Repair It (Fully Take away Guillemot)
- Delete these two folders in the event that they exist:
C:Program FilesGuillemotC:Program Information (x86)Guillemot
- Together with your FC related in DFU mode, open Gadget Supervisor, discover
Guillemot STM DFU Gadget, right-click it → Uninstall system, and verify “Delete the driving force software program for this system.” - Unplug the FC and reboot your laptop.
- Put your FC again into bootloader mode and run ImpulseRC Driver Fixer once more.
You need to now be capable to flash firmware efficiently.
Nothing Works?
I’ve personally had a pc that might hook up 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, infinite troubleshooting — nothing labored after attempting for months.
If in case you have a cussed laptop like that, there’s the work round: Use the Speedybee app in your smartphone. You’ll be able to hook up with your FC, change settings, and flash firmware identical to the desktop Betaflight Configurator.
AT32 Flight Controllers
Whenever you first plug an AT32 flight controller into your PC, Home windows usually installs the drivers mechanically, and Betaflight ought to be capable to hook up with it after just a few seconds. Within the COM Port it ought to present “AT32 Digital COM Port”. If this isn’t the case, you’ll be able to obtain and set up the drivers manually:
- Go to the MCU web page: https://www.arterychip.com/en/product/AT32F435.jsp
- Within the “USB Software 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 is likely to 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 “Software” 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
Word: the ImpulseRC Driver Fixer doesn’t work for FC with AT32 processor, solely STM32 ones.
The best way 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 might 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 “Permit” subsequent to SiLabs.
- Restart your Mac.
- As soon as put in, you’ll want to return to the identical place to permit unauthorised utility, Silabs on this case.
FAQ
Q: I’m having hassle flashing the board. DFU mode exhibits up in Betaflight Configurator, however flashing fails with this message: “Learn safety not lively. USB system efficiently closed.”
A: Strive unchecking the “Full chip erase” possibility earlier than flashing. After the firmware is put in, you’ll be able to reset your settings in CLI by typing: “default” in CLI to reset all settings.
Conclusion
Driver points are probably the most frequent 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 at all times 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 concerning macOS
- Feb 2025 – Added directions for putting in drivers for AT32 flight controllers
- Nov 2025 – Rewrote tutorial for readability and added extra detailed directions