ati 5770 can't be recognized in mac pro 2,1

I have an ati 5770 card that was working in a mac pro. Then the mac pro stopped recognizing it.
I tried it in a pc and it worked fine.

I used atiwinflash to backup the card rom and tried to reflash the bios with a mac 5770 rom from netkas and now the ati card is not recognized by a mac or pc.

Is there a way to get this card working again?
Is there something I can try on a mac or pc to unbrick the card?