Hello CavalerPk, I’m sorry for the inconvenience that you have faced with your system.
I would need you to please send me a picture of the status of the RAID once you access the RAID BIOS on your computer. I would like to see if it is possible to recover the array on its previous state, since this type of status is unrecoverable.
I recommend you to back up all the information before performing any more troubleshooting.
As I mentioned, maybe not clearly - if I boot into Win8, I can see RAID and its contents without any problems, so data is not lost, at last for now.
I just cannot see it from BIOS and therefore cannot boot into system installed on RAID.
I guess maybe drivers which came bundled with Win8.1 "upgraded" some internal RAID markup in the way old BIOS (Intel option ROM to be correct) cannot recognize it any more.
In this case I wonder which version of ROM could recognize it and maybe I can flash it somehow...
Yes, I've found that forum, and asked there as well. Though I wanted to see if there is some more official point of view on that matter.
Anyway it doesn't look like drivers problem - more of a BIOS problem.
thanks for letting us know.