I tried the 3900 patch on top of 2.03, I got the Memory error so turning off Bluetooth was a real pain in the rear. Especially now with 2.03, when I turned on bluetooth, the bubble asked me if I wanted to turn ON flight mode. The only way I could figure out to turn on the CDMA radio with the bluetooth on, after a reset was to call something (like *86) It would never complete the call but the CDMA radio came on.

Second point to the story, if you want to use your phone without your BT headset and without turning off bluetooth: goto -> Today -> Bluetooth Icon -> Bluetooth Manager -> Click & Hold your headset icon -> Hands Free Settings -> Uncheck the Use Hands Free For ...
Then you can use the phone normally.

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AT&T Jailbroken Iphone 3G 2.2