Sorry for the late response to above post. Yes, I got it to work, but it took some effort. When the installed new 12.1 DVD wasn't working, I ended up doing the following:
o unloaded new 12.1 DVD
o turned key off, waited a few seconds, loaded old 11.1 version
o turned key off and waited a while
o turned key on and unloaded old 11.1 version
o turned key off and removed radio fuse in engine compartment
o waited 30 seconds (I think instructions say to wait 10) and reinstalled radio fuse
o turned key on and notice radio presets were gone
o loaded new 12.1 DVD
o system loading progress bar appeared on screen (working!)
o tried tapping top left corner, then bottom left corner, then top again, then bottom again... menu popped up with override option on left side
I had tried variations of the above sequence (like removing fuse after removing 12.1 version and trying to reinstall new 12.1 version), but nothing worked until I tried this sequence. Looking back, my guess is we need to wait 30 seconds after removing the radio fuse, not just 10 seconds.
Lost radio presets and my maintenance reminders, but no big deal to reprogram them. As with any new DVD, one must also set the region.
The link to the Craigslist ad at the beginning of this thread doesn't work anymore, but Jason may have created a newer one. He responds to e-mail questions and seems easy to work with.
