Well I did the opposite. I placed the Mac OS 9.0.1 ROM image in the 8.6 system folder. It actually booted up with the Mac OS 8.6 welcome screen. That was short lived however, it was followed by this system bomb message. "Sorry, a system error has occurred. unimplemented trap To temporarily turn off all extensions, restart and hold down the shift key." No damage was done. I just rebooted into OS 9 by holding down the option key. I was wondering though, since it actually gave me the OS 8.6 welcome screen followed by the system bomb if might just be possible by tweaking something. :?: