Can an eMac boot from a USB optical drive connected via a FireWire adapter? I've got an eMac that's mostly working (running Tiger, plus a selection of other nice software), but has a broken optical drive.  I have a spare USB optical drive lying around, and it works for most purposes, but, according to this discussion on the Ars Technica OpenForum, most PowerPC Macs (including eMacs) can't boot from USB drives (at least not out of the box and without a LOT of tinkering and swearing), although they can boot from FireWire drives.

Just in case I ever have to reinstall Mac OS X on the eMac, here's my question: if I plug a USB-to-FireWire adapter into one of the eMac's FireWire ports, and plug the USB optical drive into that, will the eMac be able to boot from said optical drive, or will I have to shell out for a FireWire optical drive?
I believe you’ll have better luck with USB drives that are not optical. FireWire optical drives that supported booting in this era were expensive, so see if you can score a drive that you know used to boot. Even three at scrap prices are often salvageable with DIY skills.
I’m almost certain we booted these Macs from USB drives in the shop back in the day. It wasn’t “supported” but it worked most of the time.