Also , if it's USB 1.1 I believe those G4's (non-2.0) were USB bootable. It would be slow, but a CD-ROM (IDE) on a USB adapter and/or USB combined DVD drive should be bootable. it seemed when 2.0 came out, apple removed it. Someone said through the Open-Firmware you could make a G4/G5 boot from USB 2.0. I seem to remember trying this and it did work on an iBook G4, so you might try to figure out how. I had to select the USB device and make it load the bootloader from the disc.