Ignore that my driver is already properly installed. But your case, you would right click the STM32 in FS mode, and update driver. 


Click browse my computer for drivers. 


Then click let me pick from a list


Look for the STMicroelectronic and select the STM VCP COM driver and hit next. If you don't have the choice, you need to download the STM32 driver and run it. The exe file will install all the STM32 drivers. 


If you don't see a list of manufacturers, then unclick the compatible driver box. 

I see what you mean. I thought I was doing it manually but it asked me to find a folder.

I chose "Let me choose from a list of drivers on my computer" and chose Betaflight STM32F405, which is the same driver all the "working" quads have. It says it's succsefully installed the driver Betaflight STM32F405 for the device, yet it still shows up as "STM32 Virtual ComPort in FS mode". I go in again and say uninstall device and delete driver and when I plug back in, it shows up as the same thing again, like it's not deleting the driver.

EDIT: Sorry, just saw your post. Trying that now, thank you very much for all your help so far.

You are a genius, voodoo! It WORKED! Thank you thankyouthankyouthankyouthankyouthankyouthankyouthankyouthankyou

I think you should tell JB so he can fix his issue too - you'll get on his show...lol.

I wonder why this happens in the first place, though?

I edited my post a little bit and added some more information. Make sure you reread it again.


Also I read somewhere that if you install the wrong firmware target on the FC, it could cause this "STM32 in FS mode".

(01-Dec-2020, 05:37 AM)Eazy123 Wrote: You are a genius, voodoo!  It WORKED!  Thank you thankyouthankyouthankyouthankyouthankyouthankyouthankyouthankyou

I think you should tell JB so he can fix his issue too - you'll get on his show...lol.

I wonder why this happens in the first place, though?

I did once commented on JB video, but never got a response.

Glad it worked.

(01-Dec-2020, 05:39 AM)voodoo614 Wrote: I edited my post a little bit and added some more information. Make sure you reread it again.


Also I read somewhere that if you install the wrong firmware target on the FC, it could cause this "STM32 in FS mode".

The very first thing I thought was "maybe I flashed the wrong firmware target".  I even checked and it's RUSHCORE7, which is the name of the FC so I was pretty sure (plus I saw in a description online).  I even reflashed it again to be sure but no luck.

You helped me so much today.  I appreciate your wisdom.

The first time I started with this hobby, I figured all these driver problems out. Half the people on the forum don't really have a clue and gave all the wrong information. The fixer is a good idea, but half of the time it does not even work. The FS mode was the first time I have seen that. I am actually not even sure what is FS mode. Normally, you see a STM32 driver in the "Unknown" tree.

As to why this happened on your computer, I honestly don't have a clue. Somewhere along the line, you let Windows automatically install the driver and it just picked the wrong one. And Windows is stubborn, once you installed the wrong driver, it keeps on trying to install the same wrong driver.

Well I don't know what FS mode is either but I'm officially naming it "F**k's Sake" mode because it's a pain in the butt.

FS Mode is "Full Speed" mode. You can get that when you aren't expecting it if you have the wrong driver installed on your computer or the wrong firmware installed on the MCU.

And here, the two quads that I had problems connecting with - the firmware is the name of the flight controller (KakuteF7 and Rushcore7) so there's no way I'd mess up flashing the wrong firmware.

Although now that I think about it - those are the only two F7 boards I have. Wonder if that's a coincidence.

If after following Voodoo's excellent guide you still can't get the VCP drivers to install or work, the steps I took are found in this thread: https://intofpv.com/t-betaflight-com-port-drivers.

In a nutshell I had to uninstall all com ports, reinstall the STM32 driver package and then manually reinstall the STM32 driver for each quad to create new VCP's.

I just got through this exact issue... in my case, i was using an iflight f7 twing and tried reinstalling drivers and nothing was seeming to work. found a youtube where a guy disconnected his receiver and it solved the problem, not my luck tried this and still no connection after trying to flash. but then i disconected my caddx air unit from its plug and it works perfectly fine flashes like it was ment to. hope this helps someone

Snow had found this interesting issue:

(03-Sep-2021, 11:47 PM)SnowLeopardFPV Wrote: I did some further research and discovered that it is specifically UART1 and UART3 that cause this issue on F4, F7, and H7 FC's. So the takeaway from this is not to connect any peripherals to UART1 or UART3 on a F4/F7/H7 flight controller that power themselves up when a USB cable is connected to the FC, or if you do, make sure it's a peripheral that is connected via a plug so you can temporarily just unplug it if you need to get into DFU mode.

I know that the Caddx AirUnit is not powered via USB but could be related.

(03-Sep-2021, 11:47 PM)SnowLeopardFPV Wrote: So I'm back home now and I just tested DFU mode with my GPS module connected to UART3 on my Kakute F7 HDV FC.

Nada. Unable to get into DFU mode. I unplugged the GPS module and I was then able to get into DFU mode no problem.

I did some further research and discovered that it is specifically UART1 and UART3 that causes this issue on F4, F7, and H7 FC's. So the takeaway from this is not to connect any peripherals to UART1 or UART3 on a F4/F7/H7 flight controller that power themselves up when a USB cable is connected to the FC, or if you do, make sure it's a peripheral that is connected via a plug so you can temporarily just unplug it if you need to get into DFU mode.

I have a JHEMCU GHF420AIO (F405 MCU) which came loaded with Betaflight 4.2.0. I'm running BF version 4.2.11 on all my quads (waiting for the 4.3 official release) and so I wanted to flash my flight controller.  I tried everything under the sun but I could NOT get it to boot into DFU mode. Then I found this thread quoting an older post by SnowLeopardFPV and considered that I had connected my TBS Crossfire Nano Rx to TX1/RX1 (UART1).  With nothing to loose, I desoldered the 5V power to the receiver and, violia, I got into STM32 Bootloader with no problem. I've never heard of this issue before but I'm guessing that all manufacturers just know to avoid UART1 and UART3 for precisely this reason.

Thank you very much!

Here is the link to that thread from August 2021:
https://intofpv.com/t-kakute-f745-hdv-df...i2c-errors