See https://wiki.ubuntu.com/PowerPC.

Note: The following has been tested on a Mac iBook G4 (mid 2005)

Ubuntu 10.10 PowerPC

USB device installation

  • Use 'Startup Disk Creator' from the System > Administration menu from an i386/x86-64 Ubuntu installation (as the PowerPC version of Ubuntu doesn't support SYSLINUX, but the install CD contains the yaboot bootloader that is required, and it will be transferred to the USB).
  • Choose the downloaded Ubuntu Desktop 10.10 PPC .iso file or burned CD-ROM as the Source.

Install Yaboot boot loader

  • Read the precautions at this page, Boot PowerPC Macs via USB 2.0 drives
  • Power on while holding four keys down, option+Apple+o+f. This takes you into Openfirmware.
  • Enter devalias at the 0 > prompt (See step 4 in the above reference.)
  • Note the exact usb device addresses.
  • By experimentation, I found that my USB device would boot after setting the boot-device with this command:
    setenv boot-device /pci@f2000000/usb@1b/disk@1:1,\install\yaboot
  • If the USB disc is not around, the default boot-device will boot your regular Mac installation.
  • Check your setting with this command:
    printenv boot-device
    Your system may have different addresses, so it may take a while to discover the proper address.

Dual Boot with Mac OS X Leopard version 10.5

  • Use the Mac install DVD to resize and create partitions (including swap) for Ubuntu
  • Burn the Ubuntu installation CD and install Ubuntu into the new partition by booting the CD-ROM.
  • Use System > Administration > Additional Drivers to install the Broadcom B43 wireless driver.
  • Use Ubuntu Software Center to search for Sugar. Install Sugar, the emulator for the Sugar Desktop Environment, plus dependencies and Activities suitable for Sugar 0.88