I just purchased a Firehawk FX for a small investment. The previous owner had a failed update and did not know how to fix it. I downloaded the driver plus the updater and with the program running, forced the update by holding A and C while powering up.
The update worked but immediately on the automatic restart the A button was flashing and it would not proceed to the "Starting up" status (which should occur quickly).
I figured out that if I plugged the computer in to the unit with the USB cable and then powered it on that it comes on fine. Unplug the USB and it will get stuck on the Flashing A button glitch again (if powered off and back on)., but will work perfectly if plugged back in to the computer with the USB cable and the power button cycled off and on again.
I like the unit, and the features are great. I do wish that there wasn't this issue which seems to be pretty common on this model.
As long as I can jump start it I will use it at home to practice. I wouldn't trust it for playing Gigs or anything. Unfortunate. At least I don't have much invested.
Something about the USB being plugged in to the computer is bypassing the problem, which should be a key indicator of how to fix it. Hopefully Line 6 personnel can figure out how to fix via an update with this information.
Any others who are having this problem - please try this fix on your unit and report the results. If it is repeatable on multiple units it may be a simple fix for the programmers.