This works, though I'm not convinced about how or why. My overnight connection failed two days ago, and 243/Zones connects the next day yielded the Combining Data Bug (CDB, where the update fails at that point). Connected overnight last night, but no Guide update. Still had the CDB.
Noting that I can change the zip code and still stay within my city's cable service area, I did that, it then dialed the RTV server, and that failed. Tried again several times, and it eventually completed. Did a 243/Zones connect which completed extremely slowly (took all morning), so the shorter connect time idea is in question. Guide is good now.
Getting a pattern here. I can't get an update if I have the CDB, unless I can complete a connection with the RTV server first. Then I can do a successful 243/Zones connect. This has held up 3 times now.
It shouldn't matter whether you change your phone number or zip to produce a call to the RTV server. That call is much faster than a net connect, can be repeated until it succeeds, and this seems necessary before a successful net connect will restore the Guide..