Is there a reason why you unlocked the 6950? Unless it's the original 2GB (reference design) that can be unlocked to 6970 then it's okay. Otherwise, you will have to RMA it. I am not too sure on the warranty on the card with flashing BIOS. Some manufacturers are okay with it.
It is an original reference 2GB, It unlocked fine. It's been running fine for almost a year and I just now started having these issues.