Try clearing the NVRAM (CMOS) to see if it resolves the boot problem.  Possibly the information stored in the NVRAM (CMOS) became corrupted or has a conflict with the newer BIOS version which is not uncommon.  Normally you would clear the NVRAM (CMOS) by entering the BIOS Setup, but it would appear that you can not do so.  The alternative would be to remove the battery from the motherboard to clear the NVRAM.  With the machine unplugged from the wall remove the battery from the motherboard.  Then with the machine still unplugged press the On button for several seconds to dissipate any remaining electrical charge on the motherboard.  Then re-install the battery, plug the machine back into the wall and see if it will boot normally.

I have the same problem.  Isolated it to the RAID as well.  I upgraded the BIOS to TRY and fix a problem I was having with a brand new BFG 7800 GT OC card that after driver install the screen is all jumbled (technical term).  I would like to resolve this BIOS issue if possible. Any ideas - please?

After reloading the system with no RAID and using the A06 BIOS I had the same problem with the 7800.  I went to look for the A05 download to revert back so I can get my RAID operational and pull that worthless 7800 out and I noticed that the A06 download was no longer available!  It is back now with the same publish date but that seems like to much of a c oincidence!  I would like to download it again but am afraid it will screw with my RAID again.  This video card upgrade has cost me countless hours.  I may try a 6800 OC and see if that will work.  Anyone have any advice... please?