- Options:Security options: General Settings:context menu -> wipe handheld
- Options-Advanced:Applications: delete apps that are no longer useful (no data plan)
- Insert T-Mobile SIM, restart when replace battery.
- Options:mobile network: data services off
Actually I didn’t do things precisely in this order, which might be why the phone didn’t “know” its own number (though it did ring when dialed).
The fix was:
- Options-Advanced:SIM Card:context menu –> Edit SIM Phone Number. Type in T-Mobile number.
After this set of changes it seems to work. I’ve disabled voice mail on this service, so I didn’t try to configure a forwarding number.