The readme.txt of some past BIOS update of mine includes a part about how to repair a mis-flashed BIOS. Apparantly, a very small subset of BIOS instructions is never flashed, which allows the computer to boot to a disk and start a new BIOS flash. The VGA component is killed, though, so you have to do it without seeing anything on the monitor, you have to enter the keystrokes blindly.
Sounds pretty weird, eh? I never had to try it, fortunately, but I'll try to find that readme...
Edit: Darn ... can't find it :|