I have a JB'd iP4. I do not have any phone-related Cydia apps installed to my knowledge. I have noticed that when on a call, I will tap speaker to enable speaker phone. I can hear the other party fine, but to them the call sounds like I've placed it on mute rather than speaker. I'm assuming that there is something wrong with the mic/receiver hardware. Just in case, I thought I'd see if anyone has had this issue and traced it back to a JB issue/app error. I would restore the phone and take it back to Apple, but I did my JB via Jailbreakme.com after Apple stopped signing 4.0.1 SHSH, so I would lose my JB entirely - which I'm not in a hurry to do... Apple may exchange the phone entirely for me, and MAY give me a new one with 4.0.1 (happened before), but that's a gamble and I don't want to risk my JB if I don't have to. If anyone knows of a JB issue that can cause this/can be fixed let me know. Thanks!