USB boot is different on PowerBook. Download morphos.iso and put iso image and mac_ppc32/boot.img to your pendrive.

boot ud:,\boot.img bootimage=umsd0:morphos-3.1.iso

(bootimage keyword can be shortened to bi)

Just in case someone doesnt know: to get an access to OpenFirmware on Apple machines hold down apple + alt + o + f keys.

(FAT32 partitioning is assumed. I dont know if Apple firmware supports USB boot from any other common file systems there. Amiga file systems certainly are not supported there.)

It is also possible copy all files to USB pendrive and boot using bootdevice argument. For install/update purpose using iso image is certainly better.


[ Edited by itix 27.07.2012 - 20:26 ]