> Isn't the ud alias only available on later models including the G5 Macs?
> This is a MacbookG4 5,4

The G5 Macs and the 2nd PowerBook G4 generation (Aluminum), which the PowerBook5,4 from 2004 belongs to, were concurrent computer lines, both being produced from 2003 to 2006. However, advances in OpenFirmware for either of those lines may not necessarily have been adopted by the other one.