Kevin,
Could we do something simple like not use the CMOS for Coreboot, but use a place in the EBDA to be "CMOS"? I realize that we won't be able to set it permanently like real CMOS, but we could configure it from a libpayload payload. If we put the cmos section above the ata_s structure it would be in a fixed place, which would probably help.
Thanks, Myles