RAID UEFI BIOS extension for AMD 970 chipset mobos
I have an Asus model CM1855 motherboard, which uses AMD 970 chipset and AM3+FX-4300 CPU. I am trying to upgrade my HDD to a RAID1 (mirror) volume.
I have two identical 1TB drives installed and connected to the SATA6G ports on the mobo; one of those two is the original HDD with Win8.1-64b OS & apps installed (on SATA Port1). Latest Asus UEFI BIOS v1501 installed. In the BIOS Advanced Mode, under the SATA Configuration, I have set SATA Port1-4 to "RAID" mode (previously was set to AHCI). There are no other options available to set RAID volume config at that time. After saving/rebooting and immediately going back into BIOS, I expected there to be new RAID config options showing up this time in the BIOS UI, either as a new item under Advanced tab or as another tab by itself...but no, no such thing is available. Thus, the RAID extension BIOS is not showing up anywhere (aka "OPRam/OpRom"), and there is no key sequence prompt hint during the reboot to go into such an option RAID BIOS. Of course, I need to be able to configure RAID options (specify drives, set RAID level, etc) in order to proceed, even if I wanted to do a fresh OS install (which I prefer not to, as I'd like the RAID controller to do it's mirror process automatically just like I'm used to with Intel Matrix/RST).
It feels like the RAID UEFI-compliant BIOS is completely missing, but I'm not sure if I'm just missing something I need to do to get it to display. If it is missing then (1) why is the main BIOS even offer a SATA RAID setting and (2) where can I download an AMD 970 RAID option BIOS that may work with my mobo?
Asus Tech Support is claiming they don't help customers configure RAID, and referred me to AMD, Best Buy Geek Squad, etc. The Asus Republic of Gamers forum discusses similar sounding problems with their ROG models, they all seem to use the Intel RAID controller chipsets (thus IRST), so that isn't helpful to a guy like me that is working with AMD 970 chipset. Altho Asus does have a RAID "driver" download for my model (listed under Win7-64b, not Win8-64), that is obviously the Windows driver for OS install, which won't do me any good if I can't get the RAID volume configured in BIOS first.
Thanks mucho in advance for any ideas/downloads/etc you can help me with.