OK, I'm just going to give you the behavior of my N810 + BT headset before and after my reflash tonight.

Before:
When the headset was attached, all sounds from my n810 would come through the headset. Even after prolonged periods of sitting, as soon as there were sounds to be heard, the headset would kick back in and work.

When Internet Call would ring for SIP calls, it would play the set ringer through the headset.

Also, I could have media player playing through the headset, and when a call would come in, the music would stop and I would just hear the ringer and subsequently the call. After the call ended, media player would kick back in.

NOW
Even when attached, no sounds come through. I have to put on media player, or another program that produces sound, turn off the headset and then turn it back on. THEN the sound kicks in.

Then (and only then), when Internet Call rings, the headset plays the system ringer along with the headset's internal ringer (which I never heard before).

And, if I have media player playing and a call comes in, the music continues to play alongside the call audio.

I don't understand what's happening.