PowerMac G5

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The PowerMac G5 was a computer designed by Apple using the PowerPC 970 processor, based off of the POWER4 ISA. Processor models are as follows

  • PowerPC 970
  • PowerPC 970FX
  • PowerPC 970MP

The 970 was used in the 7,2 PowerMacs. The 970FX was used in the 7,3 and 9,1 models. The 970MP was used in the last generation 11,2 models. The 7,2 models are as follows:

  • 1.6 SP 970
  • 1.8 SP 970
  • 1.8 DP 970
  • 2.0 DP 970

The 7,3 models are as follows:

  • 1.8 DP 970FX
  • 2.0 DP 970FX
  • 2.5 DP 970FX
  • 2.7 DP 970FX

The 9,1 models are as follows:

  • 1.8 SP 970FX

The 11,2 models are as follows:

  • 2.0 DC 970MP
  • 2.3 DC 970MP
  • 2.5 DC DP 970MP

SP for Single Processor DP for Dual Processor DC for Dual Core All models except the 9,1 model were clocked at twice the rate of the front side bus. The 9,1 was clocked at thrice the rate.

Flashing the BootROM

The PowerMac G5 A1047 BootROM is stored on a 1MB AMD AM29LV008BB 40 pin TSOP. Flashing any BIOS or BootROM will always have inherited risks. If the flash is unsuccessful or corrupted then your machine will not boot after it shuts down. The only way to recover after that would be to de-solder the chip and use an external programmer to reflash it. Always backup your BootROM FIRST and only flash trusted ROM files.

FlashROM for PowerPC can be used to read or write to the BootROM without an external programmer. It must be run within a linux environment and will not work within Mac OS X.

There have been some reported problems booting into LUbuntu using some Nvidia based graphics cards. This process has been tested on an ATI Radeon 9600 card that came stock with most A1047 models.

  1. Download LUbuntu 16.04 and burn the ISO to a DVD - http://cdimage.ubuntu.com/lubuntu/releases/16.04.1/release/lubuntu-16.04-desktop-powerpc.iso
  2. Press and hold the power button on the PowerMac G5 until you hear a long beep followed by the startup chime
    1. This places the machine in Programmers Mode and will automatically place you at the OpenFirmware prompt. The BootROM cannot be read/written to without the machine being in Programmers Mode.
  3. Insert the LUbuntu 16.04 DVD in the machine. Use the eject cd command to open the DVD tray if it was not already inserted beforehand.
  4. Boot to the CD using the command boot cd:\\:tbxi
  5. When prompted with the yaboot bootloader, you can either wait for it to load automatically or use the live command to continue booting to the LiveCD
    1. Booting the machine fully may take a few minutes. The screen may turn off several times during this process.
  6. Once you reach the desktop, use the terminal (CTRL-ALT-T) to download FlashROM and setup your environment
    1. cd Desktop to have all the files on your Desktop instead of the home folder
    2. Download FlashROM for PowerPC from dosdude1's website wget http://dosdude1.com/files/flashromppc.zip
    3. Extract the flashromppc.zip file by double clicking it and pressing Extract.
  7. Run FlashROM
    1. sudo ./flashrom without any arguments will test if FlashROM can identify your BootROM. If it cannot see or read your BootROM, ensure that your machine is in Programmers Mode.
    2. If you are attempting to READ/DUMP your BootROM, run sudo ./flashrom -r 1.bin which will create a 1MB .bin file called 1.bin on the desktop. This can then be transferred off of the machine using the web browser or by being SCPed to another linux machine
    3. If you are attempting to WRITE to your BootROM, download the ROM to your desktop and run sudo ./flashrom -w ./NAME OF ROM FILE to write it
      1. The ROM file MUST be 1MB in size in order to be written. Not larger or smaller. Do NOT try to force a smaller/larger ROM onto a chip that doesn't support it!
      2. Optionally, you can verify the BootROM's contents against the ROM you were trying to flash to see if it was successful by running sudo ./flashrom -v ./NAME OF ROM FILE