4870.ROM     - ATI's Mac Rom I used to create the patch from.
FIXROM.PY    - The patch script.
ORIGINAL.ROM - My original unpatched rom dump.
NEWEFI.ROM   - The patched rom with EBC bios and bootscreen capability.


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Assuming you have the same model card as I do 

Radeon HD4870 1G Dual DVI
PN 288-20E85-230AC

Then boot to DOS and 

atiflash -s 0 newefi.rom

