I had the problem with OS boot via SATA (because of RAID) on motherboard A7V600-X. In RAID mode OS can't boot via one SATA disk- because RAID mode require two SATA disk.
I see that other people also have a similar problem (on Asus FAQ and other sites).
I solve that problem with BIOS which have RAID disabled.
This version is non-RAID BIOS for A7V600-X ver 009.
Already tried it? Give your review.