Flashed FX4500, any ROM experts here?

Discussion in 'PowerPC Macs' started by MisterKeeks, Feb 6, 2016.

  1. MisterKeeks macrumors 68000


    Nov 15, 2012
    I successfully flashed the FX4500 for my G5 that had the RAM chips on the back. Decided to see what happened if I used the other card without RAM on the back, got the usual garbled/corrupted video.

    I thought that I'd put the ROMs that I pulled off of these cards here. I know literally nothing about ROM editing. I imagine that the two PC roms are relatively similar. Would it be possible to effect the changes made to the ROM on the compatible card to the incompatible card? IE whatever needed to be changed on the working card, change it on the non-working card and leave the rest of the non-working card's ROM unedited?

    Any ideas?

    The Backup.rom is the backup of the working card
    G5.rom is the G5 rom
    nochipsb.rom is the backup of the nonworking card.

    Attached Files:

  2. Hack5190 macrumors 6502a


    Oct 21, 2015
    (UTC-05:00) Cuba
    In mid-January I tried my hand at flashing video cards for the PPC. First was a Radeon 9250 PCI 256MB, it's now only use is as a paperweight. Then I flashed a Radeon 9600XT AGP 128MB, it's also a paperweight.

    So I consider myself an expert in making paperweights :)
  3. MacVidCards Suspended

    Nov 17, 2008
    Hollywood, CA
    I personally wrote the vaunted 7800GTX512 rom. It was based on the Q4500 rom using parts from the PC 7800GTX 512 rom.

    And it was NO FUN AT ALL to write. There are 3 or 4 people who could do this other than me. Sadly I have no time for this, and it requires a GREAT DEAL OF TIME, and the ability to test. I long ago sold my last PPC machine.

    I can tell you that comparing the roms I mentioned would have most of what you need to know.

    PPC roms were F-Code. They were oddly sprinkled with a tokenizing string that was 8 or 10 or something like that bytes long. It was like a song chorus. So the important parts of the rom were regularly broken up by those tokenizing strings. There was a detokenizing tool that helped, but only to look at. You had to do the edits to the real file.

    So you would need to compare the PC BIOS of the two 4500 cards, the RAM strings have 8 sets of values for each section. Only one of the 8 is actually used by a specific card, this was determined by straps at the open of the rom. COmpare the chips on back with the no chips on back card, find the RAM string differences. Then find the same strings in between the tokenizing strings in the Mac version and replace the same strings. You might get lucky.

    You might also try the 7800 GTX 256 meg rom, it may have right density strings, I seem to recall something about chips on back of those.

    Sadly, this is not an easy thing and I doubt that it will ever happen.
  4. oi!, Feb 20, 2016
    Last edited: Jul 14, 2016

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