Hmm, I guess that rules out bypassing the headunit fiber optic wiring. The replacement headunit is a new OEM, but is one of the later versions without the optical outputs and is not MOST-enabled.
I read in another post (http://www.e90post.com/forums/showthread.php?t=503708
) where you can go into the TCU module and deactivate the error, but there was no follow-up to report if it worked. I haven't tried that yet. Looking at my dealer-printed options list, I don't have $612 on the list. I do have $639, which is "Complete Prep, Cellular Phone USA/CDN". I think
BMW Assist falls under this VO code, but please correct me if I'm wrong.
Still open to any other ideas you might have!