There are two versions of Mac OS 9.2.2 with different support for ATA hard drives. Apple has 'silently' upgraded 9.2.2 (without giving it a new number) to recognize the new ATA 100 bus on the Dual Processor ("mirrored doors") G4s. These machines include the dual 867, dual 1GHz, dual 1.25 GHz.If you install a hard drive containing an 'old' version of OS 9.2.2 into one of these machines 3 empty ATA slots and boot directly from that OS 9.2.2 drive, the internal hard drive on the ATA 100 bus (and any partitions on it) won't be recognized.Contact Apple Tech Support for more information.