Trying to update Flycolor OMNIBUSF4SD FC using Betaflight 10.9. I have watched multiple videos and tried multiple work-arounds to no avail. 

Current FC has BTFL 4.0.6. 

I am able to connect FC to Betaflight and Load Firmware, but get stuck "Initiating reboot to bootloader". Per the video instructions, I updated the drivers and when I execute Flash FIRMWARE, the "DFU STM32 Bootloader" populates the device port. I've tried flashing the firmware with most everything unplugged from the FC with the same stalled outcome. 

When I try to flash with "no boot sequence" selected, the status goes to "Loading bootloader", then a red banner "No response from the bootloader; programming FAILED".

I've tried the above on 2 computers (Windows PC and MacBook OSx), and multiple cables, with the same results. 

Any insight and assistance would be greatly appreciated.

My (new) LED lights aren't working (another Thread) and trying to update BTFL in an effort to see if that works (nothing else has)...

Thanks... LCS

Have you tried holding down the boot button while plugging in the USB cable to manually put the FC into bootloader mode? If you do that it is also best to switch on the "No reboot sequence" option. You should also always switch on the "Full chip erase" option.

When you say "I've tried flashing the firmware with most everything unplugged from the FC with the same stalled outcome.", what is actually still left plugged into the FC, and is anything still connected to either UART1 or UART3?

Are you using the boot button to get it into DFU mode before flashing?

I ask because you say "...when I execute Flash FIRMWARE, the "DFU SMT32 Bootloader" populates the device port." I take that to mean you see the DFU bootloader pop up in device manager after you hit Flash Firmware (more importantly, DFU isn't there before you hit flash). From my experience, when you use the boot button during power up, you should see the DFU in device manager, even before opening up Betaflight to flash.

[edit:... NM SnowLeopardFPV beat me to it.]

I have tried holding down the boot button and when I start BFLT, the DFU STM32 appears in BFLT. But when I try to select the FC and firmware version, it won’t connect and won’t find the drone. I’m obviously doing something wrong…

Also, I unplugged EVERYTHING not soldered to the FC…. camera, VTX, Rcx, speaker/beeper.

I was only trying the update to see if that would get my LED light kit to work. Knowing that theory isn’t the issue with the light kit, I may just drop the firmware update. I’m fairly tech literate, and it seems silly that it isn’t working, and isn’t as intuitive as one would think… ??‍♂️??‍♂️

I have the same problem and have followed the betaflight instructions for flashing using the boot button on the fc.

I have this issue, and it started mysteriously without any changes on my part. I'll connect to the PC, pops up in BF config, select flash, autodetect, it shows, load, it loads, flash, it errors out as it cannot connect.

I then have to connect again, press the activate DFU mode IN BF, then go back to the flash section, it should still have my selected image, load, flash, done!

It is strange, as it just popped up. Maybe some windows update changed something, but I've reinstalled BF and still the issue is present.

I've given in to the horrible software and just accepted that is the junk they want people to use, and they don't seem too bothered with the issues people are saying they are having. But maybe it's just you and me with any issue with BF?