The G4s were the period during which Apple transitioned from Classic MacOS to Mac OS X. Early G4s all could boot Classic. The last few couldn't. No G5s can. (

The G4s were the period during which Apple transitioned from Classic MacOS to Mac OS X. Early G4s all could boot Classic. The last few couldn't. No G5s can. (Note: all PowerMacs that can run Mac OS X 10.0-10.4 can run Classic inside the integrated "Blue Box" VM.) The Mirrored Drive Door PowerMac G4 models that come with Firewire 800 can't boot Classic natively. Others after that, such as the Mac mini G4, and iBook G4, can't either. Apple disabled Classic from booting by modifying the later machines' firmware. A community of hackers has been finding ways around this, and now for some models there are special editions of Classic MacOS 9.2.2 that later G4 machines can run, which they couldn't at launch. G4 MDD version: http://macos9lives.com/smforum/index.php/topic,2143.0.html http://macos9lives.com/smforum/index.php/topic,2143.0.html Versions for iBook G4, Mac mini G4, and PowerBook G4: http://macos9lives.com/smforum/index.php/topic,4366.0.html http://macos9lives.com/smforum/index.php/topic,4366.0.html