Back in January 2011 i bought a HIS 6950. Didn't flash it to 6970 since my CPU was the bottleneck back then.
Just upgraded my CPU to an i5-3570K, using and ASROCK Z77 board. Tried to flash the 6950 to 6970 - and failed.
First, i verified that my 6950 is a reference design card. Backed up the card's bios and calculated the md5 sum: It matches the md5 of the reference card's bios of that time (same file as orig.rom in the 6950 -> 6970 package).
So downloaded the Sapphire 6970 that is linked in the article. Made sure bios-switch was set to "1". Used ati_winflash_220.127.116.11 to update and rebooted.
Some beeps and the screen is blank.
With the fail-save bios i booted and flashed "1" back to my backup. Verified the check sum of the downloaded 6970 file - everything ok. Retried flashing. Same result.
Now, i guess some shaders of my card are defective or it doesn't like the 880MHZ (which is unlikely since its just a 10% increase).
Can you confirm this as the most likely cause or might there be a chance that something else like RBE might work?
(I don't think the card was laser-cut since it was manufactured back in 2010, and back then AFAIR the cards were not laser-cut, that started a few months later).
PS: I also tried flashing using the 6950->6970 package, which uses an older version of the ati_winflash, same symptoms.
PPS: could the integrated graphics of the CPU pose a problem?