I bought a new PowerBook G4 15in with a combo drive. I also had a Pioneer DVR-107D DVD-RW, which I put into an external FireWire/USB 2.0 enclosure. Unfortunately, my shiny new PowerBook would not recognise this external device when connected to the FireWire port. I tried Disk Utility, and the iApps, but nothing would see or mount the drive. I even trolled though macosxhints.com to see if there was some Terminal hack I could apply ... but since the PowerBook could not 'see' the device, there seemed nothing I could do.
On a whim, I powered down and changed the connection from FireWire to USB. Bingo!
Up came everything. I was able to install iDVD and Garage Band from my iLife 05 DVD with no problems at all. Toast 6 Titanium recognises the DVD writer, and now Apple System Profiler does as well, with the rather cryptic message Burn Support: Yes (Apple Shipped/Supported).
And guess what? After a restart and swpping of cables back to FireWire, the external device is now recogised equally as well. FireWire mystery No 211105...
Mac OS X Hints
http://hints.macworld.com/article.php?story=20051119160132991