X850 XT in a G4 Quicksilver

Discussion in 'PowerPC Macs' started by NinjaTurtle, Oct 19, 2008.

  1. NinjaTurtle macrumors newbie

    Oct 19, 2008

    I purchased a used ATI X850 XT AGP 2-slot for PC, not the single slot found as OEM on PowerMac G5s. The goal is to flash it with the equivalent Mac bios so that I can use it in my Mac G4 867MHz Quicksilver (2001). By the way, I already know that I have to cover up pins 3 and 11 in order for an 8x AGP card to work in my Apple 4x AGP slot.

    Anyway, I confirmed that the PC card works on an AGP Dell Tower. I used the latest ATIFlash utility from TechPowerUps to create a DOS boot floppy, saved a copy of the original bios on the X850 XT, and then flashed it with a reduced X800 XT ROM from Mac Elite Wiki (filename "ATIhack_x800xt_reduced.rom", which I renamed to x800xthk.rom for the floppy). I used the following command "atiflash -p -f 0 x800xthk.rom" (confirmed that "0" was the right slot).

    Well, I think it flashed, because the log file said it flashed 10000h (64K in hex) bytes; it said to reboot in order to complete VBIOS update, but of course it didn't do anything on the Dell because the card was now MAC-ified (new word?).

    Back home, I placed it in Quicksilver (Leopard) AGP slot...again, pins 3 and 11 are covered with tape; I also have an old Rage128 PCI card that I used to boot up into the Finder. But, the X850 XT just sits there with the fan blowing full speed and my monitor's LED stays amber and the screen black when I plug in the VGA connector.

    Any thoughts? Perhaps someone has better BIOS files for me to use?

  2. OrangeSVTguy macrumors 601


    Sep 16, 2007
    Northeastern Ohio
    Flash it on your Quicksilver since you do have a PCI card. Try downloading the 128kb Rom instead of the reduced rom. 128kb Radeon X850XT
  3. TDM21 macrumors 6502a


    Jul 7, 2004
    Maybe the Device ID is mismatched. Many of the ROMs are written for a particular card with a specific ID number and if that number doesn't match what is in the ROM then it can cause issues. If you backed up the original PC ROM then you can open it with a hex editor and find out what the Device ID is. If not, then you may have to do some google searching to find out or see if ATIFlash can read it.

    Once you know the Device ID of your card open the Mac ROM up in a hex editor and search for the old device ID. I used NVFlash Utility from Graphiccelerator to find it was 4A48. You be able to find it in two different places in the ROM. Once you change the device ID to the one from the card, reflash it and see if the card works. NOTE: If you do the hex editing on a PPC Mac, the ROM's bytes will be read in reverse. So instead of searching for 4A48 you will need to search for 484A. Also enter the new Device ID in the same manner: last to digits first.
  4. NinjaTurtle thread starter macrumors newbie

    Oct 19, 2008
    Flashing on Quicksilver...I thought that would work, but the Flasher and Dumper that came with Graphiccelerator could only see the Rage128 in the PCI slot; nothing was seen on any other slot. Does this perhaps support the "Device ID mismatch" theory?

    Let me add some background info:

    1. Copied original PC Bios off the card on Dell tower using ATIflash. Info from ATIflash: PCIID (4B491002), SSID (03121002), Micro (R420/M18), Flash (M25P05/C 64KB), Bios P/N (113-A47504-101).
    2. Took home to use with G-accelerator; it couldn't see anything on AGP, only PCI. Went back to lab at work...
    3. Used ATIflash to (successfully?) program the hacked reduced X800 XT Bios into the X850 XT. The log file is attached.
    4. Back home, nothing from X850, only the Rage128/PCI.
    5. Joined MacRumors for your expert :D advice!

    Now let's talk about the Device ID...

    Note that during #2 the original ID was 4B49, so did G-accelerator ignore the card because it couldn't identify 4B49? Or maybe it read it as 494B (Big-endian, thanks for reminding me)? If it ignored the card because of an unfamiliar ID, then maybe the suggestion to change it to 4A48 will work.

    However, during #4, the card supposedly had the new ID from the reduced ROM. So does this mean that the ROM is NOT the only place where the ID is stored on the card; is it hard-coded elsewhere (resistors, fuses)?

    Attached Files:

  5. TDM21 macrumors 6502a


    Jul 7, 2004
    Hmmm, you might try a different version of ATIFlash. The best advice I can give you is to head over to the StrangeDogs forums http://strangedogs.proboards40.com. These were the guys who worked on getting the ROMS to work on PC cards. They later moved to become TheMacElite, but the guy keeping that domain up disappeared. So now they are back at strangedogs. There is a tread under "Flashing and Experiments" that is was dedicated to the X800 (27 pages worth). If you can sift through all the information you might be able to find what you need.
  6. InvisibleCow macrumors newbie

    Feb 28, 2009
    Hattiesburg, MS
    I'm having the same issues with an X850 Pro (same hardware, different configuration). Trying to build the ultimate QuickSilver, and this graphics card is key! Reduced the ROM as directed by TheMacElite site, flashed and taped, black screen. Also, the fan never started... is yours doing the same?

    Thanks everyone for the hints so far, and I'll update if I have any luck with the thing.
  7. turnkit macrumors newbie

    Dec 21, 2009
    Here it is 2012 and now a Radeon X850 XT can be had for $40 on eBay.

    I have a lab of twelve 933Mhz Quicksilver 2002's, half of which I'd like to upgrade to X850's if I can.

    If anyone has had any success in flashing the 850's please post a follow up! THANKS!

    PM me to turnkit@gmail.com


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