Recently I was trying to flash the firmware for a iFlight Succex F4 Flight controller(its part of the iFlight Succex micro stack V2.1) and I ran into a problem where it would flash and the progress bar would load up to 50 percent and then it would stop and I would receive a message that said "Usb port closed". Has anyone seen this before and how do i fix it?? Because now I have a flight controller with no firmware and I can't flash new firmware too it because of this. Thank you ahead of time.

Hold the boot button when you plug in the FC to USB. This will get you into DFU mode. Then try flashing again.

(14-Jan-2021, 09:54 AM)voodoo614 Wrote: Hold the boot button when you plug in the FC to USB. This will get you into DFU mode. Then try flashing again.

Yep I tried this and it still stops about halfway and says USB port closed

(14-Jan-2021, 08:53 PM)Kindactor Wrote: Yep I tried this and it still stops about halfway and says USB port closed

On some FC you have to try a few times. Otherwise, try it on a different computer.

(14-Jan-2021, 10:27 PM)voodoo614 Wrote: On some FC you have to try a few times. Otherwise, try it on a different computer.

Do you think I should do the full erase mode and then try and flash the firmware in boot mode?

I have the exact same issue, halfway though the flash loading bar the log says usb device closed successfully and I am unable to access the Fc now, did you ever find any form of solution? I have redowloaded drivers, betaflight configurator and tried multiple configurations of the options such as full chip erase
Betaflight worked fine for my hornet and my tinyhawk?

(29-Mar-2021, 06:33 PM)yopz Wrote: I have the exact same issue, halfway though the flash loading bar the log says usb device closed successfully and I am unable to access the Fc now, did you ever find any form of solution? I have redowloaded drivers, betaflight configurator and tried multiple configurations of the options such as full chip erase
Betaflight worked fine for my hornet and my tinyhawk?

So you have tried to reflash multiple times and still failed?

I still have a quad with a Lumenier LUX F7 Ultimate Flight Controller that suffers from similar issues while updating the Betaflight firmware.

When I first got the FC, i connected it to my laptop and updated the firmware. Set it up on the quad and everything was perfect.

A few months later I decided to update the firmware to the latest Betaflight release at the time, and it would stop half way through the flashing process, sometimes while enabling the boot loaded, sometimes with USB serial port errors.

I dismantled the quad and unpluged the camera, gps, vtx, esc and it started behaving normally. After plugging the stuff back in and testing for the failure point, I managed to narrow it down to the GPS.

The GPS works perfect till this day on the same FC, but everytime I need to update the firmware I have to unplug it.

Sorry if that was a long story but I hope this helps track down your issues.

I would suggest you unplug everything and connect the barebone FC to your pc/laptop to perform any troubleshooting.

Try another usb port, restarting your computer, try another usb cable (not all cables are made equal as some are only charging cables and do not have data connections), unplug any other usb devices connected to your computer, try another computer.

I was having the exact same issue just now.  Hence I came here searching for a fix and found this thread.  
Tried to flash my Succex f722 again and noticed that betaflight had auto loaded the Succex H722 firmware.
I moved to the F722 FW and it flashed successfully.  
Hope this helps.

Anyone have a fix for this? I tried several different releases and still the same issue. Very frustrating

(25-Jul-2021, 01:36 AM)Rooster7435 Wrote: Anyone have a fix for this? I tried several different releases and still the same issue.  Very frustrating

So you can connect to BetaFlight but not update the firmware? 

Have you tried a different machine? Are you on Windows OS?