I have a friend with a mac pro 2008 model - which is failing to boot. Windows 7 was the predominantly used OS on it, and she hardly ever booted into OSX Snow Leopard. She did change the graphics card at one point, but I dont think she booted into osx once after installing the replacement gfx card (xfx 6870).

She tried to boot into OSX by holding the option key - but just received a blank screen and no video output. When booting into windows, and selecting the 'boot into osx on reboot' option - now there is no video output at all - and no option to select boot OS - so we're really stuck now. There are two chimes on boot.

I really have no experience with Macs - and have no idea where to start troubleshooting this problem. Any help would be appreciated!

Edit: I have done some reading and possibly the reason there is no video is because the xfx 6870 model has not been flashed, and doesnt support the efi-bootcamp menu.

Edit: Are there any keyboard shortcuts to select the OS on the bootcamp os select menu?

Edit: Finally got windows 7 booting again after digging out the broken 8800GT. Now just need an idiot-proof guide on flashing the 6870 so it works in osx!

Edit: After doing some reading - it appears that the last version of snow leopard should have support for the 6870 - so I will probably try booting to OSX with the old card, then running the system update - and hope that the old gfx card does not fail completely during this time. Then - if we can boot into OSX with the 6870, we will try using this zeus tool http://www.groths.org/?tag=zeus - which appears the easiest way to flash the card.

  • I had have a MacPro that failed to boot or more accurately repeatedly attempted to reboot without success. Eventually I found that replacing the keyboard was the solution.
    – BondedDust
    Sep 19, 2019 at 17:25

2 Answers 2


You could try setting the PRAM. I think that was still effective on those models. But you are probably right about the graphics card. You can still pick up "cheap" cards from places like Powermax or powerbookmedic or owc

  • Would mountain lion support the 6870 out of the box? Is it worth just trying to upgrade? Tried resetting the pram - I think it's because the osx installation has never been setup to use the 6870 and we cant see the bootcamp menu..
    – Andrew B
    Oct 21, 2012 at 23:16
  • It might. I found this thread: insanelymac.com/forum/topic/…
    – ICL1901
    Oct 22, 2012 at 0:42
  • and this one. tonymacx86.com/mountain-lion-desktop-support/…
    – ICL1901
    Oct 22, 2012 at 0:42
  • 1
    You may need to use a second computer to boot from, using the main as an attached system, then add/replace the kexts. Sorry for all the comments, I keep pressing RETURN by mistake.
    – ICL1901
    Oct 22, 2012 at 0:43

The Mac should boot without a video card. However, a malfunctioning video card will prevent it from booting. If the original card was an 8800GT, search the web for "8800GT bake" for instructions on how to fix it by sticking it in the oven for several minutes. I've done it twice as unbelievable as it sounds and it does work. However, that doesn't sound like your issue.

You should be able to find a guide on flashing the 6870 firmware to EFI on this site. It sounds like enough people have done it at this point.

Though this post is obviously old since it is referring to Snow Leopard, I believe there wasn't really proper driver support for 6870-class video cards until Lion or even Mountain Lion.

All that being said, I have a non-flashed 6870 running in a MacPro3,1 with no issues. I haven't attempted the EFI flash simply out of laziness since the lack of boot screen hasn't bothered me enough and I've been fine with the rare occasions I boot camp into Windows 7 to use a bless script that I've put on my desktop years ago.

The only advice I'd give for anyone who wants to put in a PC card in a machine like the 2008 Mac Pro is to try to keep the wattage under 180W, avoid the latest GPU of the day (driver availability) and keep the original card somewhere in case things go wrong. Otherwise as long as your Mac boots healthy a PC card will work just fine.

All said and done, there doesn't appear to be a keyboard shortcut for which OS to boot into. You just need to have one of the OS options healthy enough and have the Apple drivers installed on the Windows side to get the boot camp options.

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