I recently unlocked my iPhone 3GS with Blackra1n to get the tethering option. The multitude of apps convinced me to stay.

One problem I've noticed now is that (sometimes) when someone calls me, the phone freezes for several seconds and drops the call. Talking to the people later they say they got a strange beeping busy signal, they never even got to my voicemail.

The same thing happens (sometimes again) when I try to make calls. The phone will freeze and then tell me the call failed. I'll have to wait while the phone goes from a single tiny bar of service to searching back to full 3G service until I can make the call.

Has anyone else encountered this problem? Is there a fix? It never happened before I jailbroke it. Any help is much appreciated.