Anyway, I took the 20 GB drive I had removed and stuck it into a 2.5" FireWire/USB enclosure, but could not get it to show up under FireWire (it worked fine as a USB drive). After a lot of trial and error, I figured out how to do it.
- Turn off the iBook
- Unplug the power cord from the iBook (really, this is key)
- Unplug the power cord from the enclosure if there is one -- I recommend you get an enclosure with a power adapter because, at least with USB enclosures, un-powered enclosures can draw too much power and the USB port gets shut down; even the one right on the iBook.
- Now plug the FireWire cable into the computer and enclosure and turn on the iBook, letting it start up on battery power
- The drive will show up on the desktop
- Plug the computer and enclosure power cables back in
I also moved the drive to the front of the FireWire chain, but I am not sure this makes any difference.

