Constant Invalid Sim/No Sim Card Installed/No Service

[PsstGreek]

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?

 

[Apollo 13]

My girl friend just got her phone today. I've been playing with it and reseted my phone and I'm getting same problem. Phone is not jailbroken either.

 

[PsstGreek]

I'm on my second micro sim, so I don't know wth is going on.

 

[PsstGreek]

The new Cydia on top of 4.2.1 I think was causing the issues. I'm now back on 4.1 with the old Cydia and so far no problems.

 

[Esteban78]

I have the very same problem. I have a iPhone 4, 3 months old, not jailbreaked.

Yesterday, I went sleeping. When I got up this morning, my whole iPhone was erased.

Syncing with iTunes or restore fails: "No SIM-card installed it says". I went to the shop for a new Sim card, but that doesn't solve the problem. The iPhone stays in 'slide for emergency'-mode.

We already had numerous problems with all 8 iPhones we bought for our enterprise (yes, antennagate is sad but true and yes, iPhone 4 is really full of faults and problems), but this latest problem is a very strange and annoying one.

Does anyone has a clue where the problem could be?