Alright, I think I will be able to do a work-around to apply the Sapphire 5870 bios. Currently about to upgrade from XP x64 to Win7 Pro x64, and then will try. Also, can someone try the new Afterburner 1.6.0 final, in the meantime? Just released yesterday. Maybe it will finally work with overvolting? Remember to change all the revelant 0's to 1's in the config file! If anyone does this, let us know what happens.
My rig is currently apart for revamp, so I won't get to this until this weekend, sometime.