Booting from cdrom

Enter OpenFirmware prompt:
power on your mac
press down [Alt], [Apple-Key], [O] and [F] during start sound
booting from SuperDrive:
boot cd:,\\:tbxi

Setup HDD

1st backup your data
a) shrink your macosx-Partition
boot from live cd and use parted
b) boot your recovery dvd
(all data on disk will be lost)
start disk util and create the partitions you need

rescue boot

start linux
Partition numer red
openfirmware> boot pci2/ata-6@D/@0:2,\\yaboot
*) on german keyboard layouts
press for char
[shift][2]@
[-] /
[#] \
[ö] :
[z] y
start macos
openfirmware> mac-boot
openfirmware hints
identify device names
openfirmware> dev /
openfirmware> ls
get device aliases
openfirmware> devalias