Alright here's my problem. My iPhone 4 keeps giving me a constant invalid sim, no sim card installed, no service pop ups. I'm using an official carrier AT&T and I'm jailbroken on 4.2.1. I don't if it's Redsn0w causing the issue because I've had the same problem ever since 4.1. Or if it's the iPhone itself. My iPhone is also set up as new. As anyone experienced this before?