LRH uses a Powerbook G4 running Tiger. For various reasons we both wanted to upgrade her Powerbook to Leopard and last night was my first attempt. It turned out to be an exercise in frustration and stupidity. Frustration for 3-4 hours lost on the project and stupidity for not realizing why it didn’t work the first time.

Usually, installing an OS on a computer is a straightforward process, especially with a Mac. However, we had the unfortunate added complication of a defective CD drive, so the install media had to be remotely mounted and used.

1st Attempt:

1. Connected G4 Powerbook to Intel Macbook Pro with a firewire cable and booted the G4 Powerbook into target disk mode. Note that target disk mode is a way of turning a Mac into a giant external hard drive.
2. Booted the Macbook Pro from the Leopard install DVD and formatted the remote drive on the Powerbook G4 to GPT. Installed Leopard.
3. Reboot the G4 Powerbook only to find a welcome screen consisting of two buttons displaying a curved arrow and a right-pointing arrow respectively.

It turns out that the open firmware on the G4 does not understand the GPT partition structure used by Intel-based macs.  Booting from Intel hardware invoked this method of installation that required GPT to be used before the OS could be installed.

What I Should Have Done:

While it should be possible to install Leopard by booting from the Macbook Pro a much easier solution is to just make the Macbook Pro appear as a disk on the Powerbook.

Booting the Macbook Pro into Target Disk Mode should make its DVD drive show up as a bootable drive on the Powerbook and the install should happen with the correct hardware being identified so the older partition structure will be used.