I personally never experienced this issue in 1.5, but in 2.1 I experienced it about 5 minutes after flashing it. I used 2.1 today all day w/o any trouble.. and I think I know how I fixed it. After installing 2.1, I messed around a bit with it and ended messing it up. I did a factory reset.. and.. no more problem with CDMA at all. I would recommend trying it a factory reset from the settings menu. A possible alternative is to go to your dialer and enter ##3282# and click Enable HFA. HFA=Hands Free Activation. I tried this and my phone rebooted and reactivated w. sprint. You may need your MSL. If you don't know how to get this number do a search..