My 12 inch powerbook does not start up. Instead it loads to Darwin. I have an install disk from a 15 inch powerbook G4 and I would like to know if using this would work on my 12 inch powerbook G4?
Generally the hardware differs enough that the drivers on the 15" restore disc will not operate on the 12", if you were intending to use it to reinstall. It might allow you to run disk utility but I wouldn't recommend using the incorrect disc to try running anything. You could call AppleCare and see if they have the correctly configured discs but they'll probably charge you around $15-$16 per disc, $32 for both.
The last couple of times I've had that problem, I've just called Apple and they've sent them to me for free. Now YMMV, but I've gotten restore discs for a Mac mini, Macbook, and powerbooks and have never actually been charged. Call, plead your case and good luck