I understand that you are trying to use hardware (pseudo) RAID on the board for better performance (RAID0). If so, you better get used to the fact that hardware RAID should only be used if you have backup on non-RAIDed disks or if you don't mind loosing all your data. See wikipedia for more information.
It's best to use software RAID, which I'm not sure Microsoft supports (Linux does that for ages, so guess what cloud servers are running nowadays?). The new BIOS version may have changed something in the RAID implementation and whoops - so goes your data on the RAID disks that were created using the old BIOS hardware RAID.
Hope you can get it work. Still, that shouldn't happen even with hardware RAID. Try contact Asus tech support via their forum site. They better have a solution for that!