I just recently came across a GA-X58A-UD3R Rev 1.0 for a small amount of money. I thought it would be nice to couple it with a x5650 to add some processing power. For testing purposes I have a i7 930 and some W35XX cpu to play around with before actually buying a x5650.

I am having some issues with it though.
Firstly, when trying to flash the F8B modded bios on it, QFlash reports too big. I then try flashspi which says bad image. @Bios however, lets me flash it properly (and have now done so many many times)
After having been flashed with @Bios (keep DMI data disabled) it reboots to the bios where I load optimized defaults. Boot back to bios where I change some setting to FORCE to make the new disk controller firmware be flashed (it worked once at least). After that I think I am done. If I boot into bios again it reports F8b, yay!

Now to the problems.

If I change some setting, for instance, I disable the splash screen and reboot.
At this point I enter some kind of boot loop, the lights on my motherboard flashes, fans start and stop, screen is never intialized and after 3-5 cycles it starts again properly.
Now when booting up screen tells me my bios crc is invalid, ie corrupt... So it automatically flashes back the F4 backup bios. This is very irritating...

So to the questions...
1) How do I stop this behaviour? I have flashed quite a few motherboard bioses in my life, but none as sensitive as this.
2) is there a dos utility that can flash 2M bioses?
3) Is it safe to say that if the bios reports F8b, I can safely flash the backup bios too?
4) If yes on question 3, how do I flash the backup bios?