tinkering and researching lead me to install Substriber Artificial Module, or SAM.
SAM's true purpose is to trick Apple/AT&T into thinking your unlocked phone is activated, so that you can use Push. Push gives you much better battery life than polling.
But the SAMprefs tool also lets you force your iPhone to be deactivated. I did that, and re-ran iTunes, and activation occurred normally
The repo is http://repo.bingner.com and just install the main app. All the addons will be grabbed automagically. My reference was:
But current RedSn0w doesn't have a "Deactivate" option, so I skipped the re-run of the JB.
I always have trouble with rejailbreaking my phone and updating it.
Erica asked me why I didn't just use non-jailbreak since it's a work phone.
There are some real usability features that I rely on. Mostly, InfiniFolders for organization, and SBSettings for travel access to airplane mode toggle, flashlight toggle, etc.
Anyway, I had it at 4.3.5 for the latter part of last week because it IS a work phone and I needed it working. But, since it's also my personal phone, Saturday was my "fix the jailbreak" day.