Don't know if this helps, but in my experience with this board (A7V133 up to bios 1007?) no drive was able to boot from the Promise ATA controller IDE ports, even when the HD was configured correctly (ie it did boot up on the primary IDE channels - which BTW also supports ATA100). This was a problem as I wanted to use the Promise controlled ports to do a RAID-0 array for better HD speed. However, I found I could use the Promise controlled IDE channels when I had a third drive for booting up on the primary IDE channels. Seems that the Promise controlled IDE doesn't function to support booting up (someone please correct me if I'm wrong). I resorted to using the primary channels only since they do support ATA 100 and I had different HD sizes (NOTE: ATA100 works only with correct IDE cables, not ATA66-type cables).