The Golden Guide to Flashing Graphic Cards
Update March 2011
Ok, this thread is a bit old, and some things here are no longer important.
For example, you can now generate automatically a 4870 / 4890 firmware in Zeus tool.
I will still leave the old text, it has some important facts.
But you should check out the Zeus thread
http://forums.macrumors.com/showthread.php?p=9427042
For current guides to flashing 4870...
The Golden Guide to Flashing Graphic Cards
Update March 2011
Ok, this thread is a bit old, and some things here are no longer important.
For example, you can now generate automatically a 4870 / 4890 firmware in Zeus tool.
I will still leave the old text, it has some important facts.
But you should check out the Zeus thread
http://forums.macrumors.com/showthread.php?p=9427042
For current guides to flashing 4870...
The Golden Guide to Flashing Graphic Cards