The last retail OS 9.2.1 CD that I have is ©2001, and we were invited to download the update to 9.2.2 when that became available. I'm not aware of any retail CD of 9.2.2 at the turn-of-Century, although I have not looked assiduously since then. OS 9 was included in ex-factory installations and system-specific CDs and DVDs for years after 2001, at least until Jan 2004. The retail OS 9.2.1 contains Mac OS ROM v8.4 at best. The update to 9.2.2 had advanced to Mac OS ROM v8.7. eMac system-specific CDs provided v9.2.2 of Mac OS ROM. The MDDs that could boot into OS 9 had Mac OS ROM 10.2.1 (with 48-bit LBA support. Don't nobody search these forums no more?).
Side-by-side with Mac OS ROM's maturation were changes to the three elements of Classic Environment (2) and Classic Compatibility ROM, which in the MDDs' case, had progressed to v2.2.1 and 9.5.0 respectively. What else these little critters enabled/disabled has to be discovered by suck-it-and-see methodology, but I can say that the version of 9.2.2 from the MDD era is as stable as a rock on Macs as far back as my two Beige G4/500MHz and 9600 G4/800MHz, and on my G4/733MHz DA. What is a necessary fiddle is to replace Apple's versions of Radeon (OS 9) software with the (later) versions from ATi. In either case, however, if you are using a Radeon 7000 (PCI or AGP), kill Graphics Accelerator. Kill. Kill.
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