Most USB sticks do not come pre-configured in such a way that Open Firmware can boot from them, so you will need to repartition the stick. On Mac systems, run mac-fdisk /dev/sdX, initialise a new partition map using the i command, and create a new partition of type Apple_Bootstrap using the C command. (Note that the first "partition" will always be the partition map itself.) Then type $ hformat /dev/sdX2 Take care that you use the correct device name for your USB stick. The hformat command is contained in the hfsutils Debian package. In order to start the kernel after booting from the USB stick, we will put a boot loader on the stick. The yaboot boot loader can be installed on an HFS filesystem and can be reconfigured by just editing a text file. Any operating system which supports the HFS file system can be used to make changes to the configuration of the boot loader. The normal ybin tool that comes with yaboot does not yet understand USB storage devices, so you will have to install yaboot by hand using the hfsutils tools. Type $ hmount /dev/sdX2 $ hcopy -r /usr/lib/yaboot/yaboot : $ hattrib -c UNIX -t tbxi :yaboot $ hattrib -b : $ humount Again, take care that you use the correct device name. The partition must not be otherwise mounted during this procedure. This procedure writes the boot loader to the partition, and uses the HFS utilities to mark it in such a way that Open Firmware will boot it. Having done this, the rest of the USB stick may be prepared using the normal Unix utilities. Mount the partition (mount /dev/sdX2 /mnt) and copy the following installer image files to the stick: vmlinux (kernel binary) initrd.gz (initial ramdisk image) yaboot.conf (yaboot configuration file) boot.msg (optional boot message) The yaboot.conf configuration file should contain the following lines: default=install root=/dev/ram message=/boot.msg image=/vmlinux label=install initrd=/initrd.gz initrd-size=10000 read-only Please note that the initrd-size parameter may need to be increased, depending on the image you are booting. If you used an hd-media image, you should now copy a Debian ISO image (businesscard, netinst or full CD image; be sure to select one that fits) onto the stick. When you are done, unmount the USB memory stick (umount /mnt).