Many will... I never made a list, but if I remember from iBook G3 to MDD will... although it has been a while; I used to strip down OS 9 and boot to USB and SCSI 100 MB Zip drives also... another reason I like the FireWire booting is "Target Mode" I would use my entire Pismo as an external hard drive by staring it and immediately holding "T" and is was in target mode... I would now connect a fresh Power Mac via FW to the Pismo FW and hold alt on the Power Mac and boot the Tower to the Pismo drive to format the internal Power Mac Hard drive and drag the OS