»HOWTO Downgrade iPod firmware?

A few months ago, my iPod (two generations old) broke. To be precise, the interaction between the computer to which the iPod syncs broke: an iTunes upgrade forced a firmware upgrade on the iPod, and the firmware in turn required a more recent version of iTunes -- which is not available with the 10.2 version of the Mac OSX. Crap.
I thought, well, I can downgrade the iPod. I keep older versions of the iTunes application bundle handy because each rev disables some functionality that I had particularly enjoyed. No such luck: one Updater helpfully noted that "An iPod is connected, but is not mounted on the Desktop." Now, if only I could force OSX 10.2 to mount the dam' thing, I'd be in business. I turned to the wisdom of the Internet.

Threads on iPodHacks and iPodBank (cache, because the site appears down) sounded helpful but did not work in practice. On the reasonable-sounding advice on these sites, I hacked various BuildIDs into the SysInfo file; restored the iPod itself to old, older, and ancient versions of the firmware; and downloaded somewhat sketchy updaters from third-party sites on the 'net. No go. What now?