HOWTO: Leopard install with Giga Designs G4 upgrade

One of my Macs is a 2001 vintage G4 733 with a dual 1.8GHz G4 upgrade. This should fit well within Leopard’s minimum system requirements, but the CPU upgrade I’m using presented a complication. Without a kernel extension from Gigadesigns called ‘Giga-Meter’, MacOS recognizes the upgraded CPU’s as ‘PowerPC 60? 467MHz’ and therefore won’t update due to the new minimum requirement of 867MHz. This extension can’t be loaded from a DVD since you’re booted from the Leopard installation CD at the time you get denied. I resolved this by doing the following (this is for fairly advanced users):

  1. Click OK to the dialog informing you your Mac isn’t fast enough, NOT RESTART
  2. You’ll be presented with an idle desktop, and will be able to choose ‘Terminal’ from the Utilities menu.
  3. Run ‘kextload /Volumes/Macintosh\ HD/System/Library/Extensions/Giga-Meter.kext’. This extension loads into the leopard kernel without difficulty.
  4. Quit Terminal, choose ‘System Profiler’ from the Utilities menu. It should now report your CPU at the proper speed.
  5. Relaunch the MacOS X Installer by choosing Terminal again from the Utilities menu and running the following:/System/Installation/CDIS/Mac\ OS\ X\\ OS\ X\ Installer /System/Installation/Packages/OSInstall.mpkg

(All on one line) Leopard install will proceed normally. Leopard also requires a CoreImage capable graphics card for a lot of its new stuff, so if people don’t have a Radeon 9600 Mac Edition in their upgraded G4’s, now’s the time to get one. This graphics card upgrade works fine under Leopard as well.