So, as I wrote before my happy world of connected technology had a dark cloud of weird behavior over it. And that bluetooth disconnect was directly caused by downloading a phone book from my phone.
Today I have finally figured out what is the problem. Simple. Duplicate entries in my HTC EVO phone book drove Sync insane and force headset part of the dual link to drop out with weird side effects (stereo audio system connect usually stays on).
Specifically, if you just happen to have two identical entries in the phone book, you’ll get this problem.
I don’t know if it’s partially Android’s fault. It could be. After all, it’s somewhat strange to have several identical records (Say, John Smith with phone number 555-123-4567), but these records are a result of, for example, importing the same (or partially matching) vcf file. I did it by accident, and my phone obediently duplicated a bunch of contacts.
Now HTC is trying to mask and solve this problem by allowing you to “link” similar contacts. So once two/three/five copies of John Smith are linked (and phone conveniently suggest it) you only see one entry. But internally the duplicate records are still there, and I guess they get counted wrong when SYNC is pulling full phonebook from the phone.
Regardless, if you are having problem with phone book download causing errors in bluetooth pairing, double-check your phone’s address book. If you are using HTC Sense based Android phone, make sure you un-link all contacts and remove all duplicates. It could be a chore, but in the end, being able to press SYNC button and say “Call John Smith at Home” could be worth it.
Downloading a hundred plus contacts still took a few minutes (all the while I held my fingers crossed, saying oh-please-oh-please-oh-please — no rational reason to do so, but helps when you’re out of ideas), and then it all worked. Hooray!