Build ppc release; don't put i386 only components into resulting image; switch to ppc branch in pd_fetch
Call host bless and ls to be able to build an image on a system of different release; replace i386-only mkisofs by a link
Lipo doesn't support -verify_arch on OS X 10.4
Bootloader and drivers: platform expert, chipset, interrupt controller, pci bus, ata on pci, pmu (proprietary, disabled) and dependence, nvram (to avoid boot slowness)