(Note: my board is the Gigabyte AX370 Gaming K7 rev 1.0 and I've been on F50a for a while now and prior to installing that BIOS I did follow the instructions of flashing to prior BIOSes before utilising BIOS F50a).
While I was in the garden the other day somebody in the household plugged in the wrong charger for a device in the kitchen and blew the plug which tripped the MCB. Upstairs, my PC was off at the time plugged into a surge protector but with the rear PSU switch on (as most people have). A couple of days after this incident I turn the PC on and it takes forever. I realise what has happened and proceed to the BIOS to set it up again, not realising it was stuck on the backup BIOS. When I did finally realise it was permanently on the backup BIOS, naturally I wanted to fix it - it's never good having only one BIOS for very obvious reasons. I was wondering why the backup BIOS wasn't automatically reflashing the main BIOS. I figured maybe the BIOS chip had died entirely. I turned off the computer, removed the battery, cycled the power switch numerous times, cleared CMOS via switch / jumper, yada yada yada, everything you can do and despite this it kept going back to the backup BIOS automatically. I tried to reflash the main BIOS but since I was in the backup BIOS (now acting as main) and despite clicking the option to reflash the other BIOS, it wouldn't work (though it didn't fail, it proceeded to 100% and rebooted and I can only guess it didn't properly work because it would expect me to be in the main BIOS and using the option to reflash both is for the sole purpose of flashing the backup when working from main). Anyway, it didn't work properly but it didn't fail either.
The ONLY option I had, and I cannot stress that enough, was to turn off dual BIOS via the board (while the system was off), set backup BIOS via the switch, go into the BIOS and then switch the jumper to main before entering Q-Flash and flashing the same BIOS revision. It worked. It brought it back. Now what I find most odd and I have read this in other threads about Gigabyte boards, is where the backup BIOS didn't reflash the existing BIOS and that what ends up happening is the BIOS switches are now the wrong way around. Is this due to moving the BIOS switch while it was in BIOS? It was the only way of fixing it. I've now turned Dual Bios mode back on but prior to this, whenever I switched between BIOS 1 and 2 on the board (when off - I only kept it on and switched to fix the original BIOS), BIOS 1 is now the backup chip and BIOS 2 on the switch is the Main bios. It shouldn't be that way around.
I've had backup BIOS restore things properly before on BIOS revisions prior to F50a and I can only surmise that something is very wrong with that BIOS revision because the backup BIOS feature didn't do its job, at all, simply from the MCB tripping in the house. I'm pleased I have both of my BIOS chips working but I'm disappointed that the feature didn't behave as it is supposed to and it required a lot of messing around before fixing it, with a weird permanent side effect to remain on my system.
TL;DR? The main backup BIOS feature didn't work properly. The main BIOS became useless, backup BIOS couldn't successfully reflash main and now the BIOS 1 switch is the backup and the BIOS 2 switch is the Main (the wrong way around - likely rendering future automatic backup features non-functional). If this isn't evidence that 3 BIOSes are more important as a backup system compared to 2, then I don't know what is. High end boards of the future should have 3.
