There are no firmware updates for a G4 alu powerbook, AFAIK. But when available, Apple would make them available for download through your software update pref pane. Same goes for updates to your Apple-supplied software. These updates will be specific for your PowerBook. You can always go to the Apple web site, click on the support tab, and click on the section applicable to your powerbook. This will show current info about repair programs, manuals and other support info.