Controller Firmware Update FAIL - will no longer sync - not even by plugging in via USB.

I have this same issue and it IS a problem. I manually updated my firmware for each of my controllers BEFORE getting by XO Seven. Now whenever I plug in the headset it prompts me to update firmware (although the sound is already working). When I try and
update it fails without giving an error, then my controller will no longer sync.

This is incredibly annoying and I hope that MS either fix the console's firmware to stop asking me to update or release another firmware update for the controller which fixes the syncing issue.

Plug your controller in via micro USB and check for firmware update.

Plug your controller into the Xbox via Micro USB. Then go to settings, devices and do a firmware update on your controller.

I was having the same exact problem. Xbox Accessories it told me that I needed to update. When I clicked update, the process failed, and the controller no longer functioned.

Your suggestion to use the Xbox Accessories seems a bit silly as it was using that app that bricked the controller in the first place.

I actually did manage to fix it though! Hopefully this helps people:

The problem seemed to be what USB port I was using. I have a USB hub, and with the controller connected to the hub, Xbox Accessories detected the controller, but attempting to do a firmware update bricked it.

I disabled bluetooth on the PC, unplugged the USB cord from the controller, turned the controller off

Then I plugged the USB (A) into a port directly on the back of my PC.

I plugged the USB (C) side into the controller, which turned it on.

(controller still bricked at this point)

I then opened Xbox Accessories app and did a firmware update.

This time the progress bar started moving, and the update was a success.

The controller is now working as intended.

I tried plugging the controller via usb in all three USB ports and with two different USB cables and every time the message says there's no controller connected via USB when I try to downgrade the firmware.