I have only tested one card and differences in cards can lead to different and unacceptable results.

This is the EXACT card I used.

Good luck everyone!

(If anyone would like me to flash their card for them I’ll do it for a fee to cover my time - leave me a comment.  Also, if you see anything wrong with my steps please leave a comment.  No cuss words or anything bad - keep it super clean!)

Comments:  Click Here

With the CD we just created in the Mac Pro - hold down the option key on the keyboard and restart your computer.  This time choose the CD to boot from.

Choose:

Enter

DOS/Linux Boot Disks

DOS Boot Disks

OpenDOS...

Then just keep hitting enter to select OK through multiple messages like this:

Notice the CD drive (UBCDDRV) - in my case it was T: (substitute as needed for you.)

Now do some DOS commands (hit enter after each command):

t: (to switch to the t: drive (if yours isn’t “t” use the proper letter)

dir (just to make sure the Mac files is there)

cd mac (to navigate into the mac folder)

dir (to make sure all of your files are there (my pictures don’t show the pc1xfx.rom))

ATIFlash -i (to make sure the 4870 is being recognized)

(notice the adapter number being 0 (zero)- not sure if your number is different to make adjustment in next step  -  I think you substitute the 0 for whatever number you get, not sure)

ATIFlash -p 0 macxfx.rom -f (this is the point of no return your card will flash)

reboot (the DOS command is “reboot” - this will restart your computer)

Power off your Mac Pro by holding the power button until it shuts itself down.  Unplug your monitor from the 7300gt DVI port (in slot 2) and put it into the 1st port (the one on the right as you are looking at the back of the computer).  Place your second DVI monitor or DVI - HDMI adapter - HDMI TV into the second port.  Also you can plug other monitors into your 7300gt if you want (I personally am using a 30” Apple Display in the 4870 1st DVI, a Dell 20” in the second, and a projector via DVI-VGA on 7300gt 1st DVI.

Configure your monitor settings in the Display section of the System Preferences.

If you have some problems just try one monitor attached to the right DVI on the 4870.  If you messed up just connect the monitor to the 7300gt first DVI and flash back to the original rom (pc1xfx.rom) by booting from the CD then in the end using the DOS command:

ATIFlash -p 0 pc1xfx.rom -f

Disclaimer:  This information simply outlines what I tried and what worked for me.  There is no guarantee of any kind and I take on no responsibility for your actions in any way.  If you brick your card or destroy your computer that is your fault.  Most of the information on this page I gathered from http://forums.macrumors.com/showthread.php?t=661681.  (THANKS!!!) This page shows how I used that information successfully for my needs.

Different cards flash with different results.  The EXACT card I bought here:

                                                  

Buy 2 power cables (yes you will need them - the ones in the box won’t work in the Mac Pro)

http://shop.ati.com/product.asp?sku=3280778

Software you will need (thanks to rew):

(Download to Mac OS side.)

The OS X drivers for the 4870.  (Probably skip this if you have 10.5.7 or later installed).  (If the link doesn’t work, Google for “MacOSX_10.5.6_radeon_hd_48x0_drivers.pkg"):

http://www.sendspace.com/file/gvsi12

(Download to Windows Side - or put on a pen drive or something to transfer to bootcamp Windows)

GPU-Z. This will backup the original ROM to restore to if you made a mistake:

http://www.techpowerup.com/gpuz/

rhildinger’s ROM this is the ROM that will make the card work on the Mac Pro in OS X and Windows via bootcamp (thanks rhildinger!):

http://forums.macrumors.com/showpost.php?p=7324217&postcount=487

ATIFlash. Use this to put rhildinger’s ROM onto the 4870:

http://www.techpowerup.com/downloads/1123/mirrors.php

Ultimate Boot CD. Used to make a DOS boot CD to do the flashing. Download the ISO version:

http://www.ultimatebootcd.com/download.html

MagicISO: Used to add software to our boot CD so we will have all the tools we need to flash:

http://www.MagicISO.com/download.htm

Mac Pro 1st Generation

Stock 7300gt graphics card

Wired keyboard and mouse (bluetooth bad for choosing boot disk and DOS)

DVI monitor

Windows XP installed in Boot Camp

(There are other ways to do this like in a PC and then transfer the card over - I’m just showing how I did it.)

In OS X 10.5.6 install MacOSX_10.5.6_radeon_hd_48x0_drivers.pkg that you downloaded from the steps above.

Unplug everything from the back of the Mac Pro and ground yourself from static electricity.

Open up the Mac Pro

Unscrew the two screws on the plate holding in the graphics card on the right side

Pull out the 7300gt card from slot one (I know the pictures shows a 2600 card-long story)

Remove the metal guard so the DVI ports can show out the back of slot 2

Plug the 2 power cables into the 4870

Plug the 4870 into slot 1

Plug the 7300gt into slot 2 (Picture wrong in showing 2600 instead of 7300)

Plug the other end of the 2 power cables into the logic board on the Mac Pro (upper left corner)

Screw the 2 screwed holding plate back over the graphics card bracket

Close the Mac Pro

Plug everything back in - Use only one monitor and plug it into the right hand DVI port of your OLD card (the 7300gt in slot 2)

Hold down the Options Key on your (wired) keyboard and continue to hold while you power on your Mac Pro.

Select your bootcamp Windows install to boot up (and click on the arrow that shows below it).

Cancel out of Windows Hardware Wizard (each time it tries to open). 

I had to insert the CD that came with the 4870 card and install the drivers before the next step using GPU-Z would work.

Open GPU-Z select the 4870 card bottom left if needed and then hit the dump ROM button middle right.  Choose a safe place to store this (it is your get out of jail ROM if you mess up.)

Maybe even make a backup of this.  Then rename one of them pc1xfx.rom

Install Magic ISO - I just used the trial.

Open MagicISO.

Double Click on the Ultimate Boot CD ROM

In the upper right section make a new folder called “Mac”.

Drag the following files into this Mac folder (see picture below):

The unzipped contents of the ATIFlash.zip

pc1xfx.rom (the original unaltered factory ROM from your 4870) - (not shown in picture)

macxfx.rom (the one from rhildinger)

Save this ISO.

Burn to a CD (see mouse position in picture)

Update with 10.5.7.  After following this tutorial in 10.5.6 I was able to update to 10.5.7 without any problem.  Upon reboot the Expansion Slot Utility (in my main hard drive /System/Library/CoreServices) launched saying that I some of my PCI cards weren’t running at full speed.  It gave me some configuration options so I removed my 7300 graphics card from slot 2 and put it in slot 4 so as to go from 1x on that card to 8x on it and have the 4870 run at 16x.  I would suggest that in following my tutorial when I say to put the old card in slot 2 you put it in slot 4 instead unless you need to use the other PCI slots - than configure how you think will be best for you.  I’m ASSUMING that this won’t change the results of the flash process.