I had the same problem - system won't boot anymore and looks almost like it is stuck after POST.
The solution was in the last page of the BIOS setup where the boot options are. There is a choice of "legacy", "uefi", and I don't remember exactly the last one, maybe it was hybrid or "auto" or something, but changing this one setting fixed the booting problem for me. It looks to me as if this default setting somehow changed with the BIOS upgrade and therefore prevented booting from my SAS SSDs.
I always upgrade the BIOS when there is an update; I know it can be risky, but on the other hand I also believe sometimes there can be small improvements, for example related to ASPM, which is important to me.
