iPhone 3G won't connect to carrier after iOS 4 update

It happened the same to me. I'm from Italy and my carrier is Vodafone IT.

I tried to put another SIM in my iPhone and it works.

In my case the SIM just got ****** up. The phone works fine.

Alessandro

My wife's phone has same issue. She's out of town and NOT happy. I updated both of our iPhone 3GSs last night to iOS4. Mine is working fine, but her phone has the issue you described with no service and number "Unknown". We have tried the obvious such as hard restart and resetting network settings under Settings->General->Reset. Apple tech support could suggest nothing else other than a Restore, which I figured I would do once she returned home tomorrow. I'm disappointed to read that Restore did not solve the problem for you.

I'll be eagerly standing by hoping for anybody else's feedback on this issue. Anyone... Anyone... ?

Update:

After spending hours reading about this issue on this forum and others, I saw someone's suggestion about cycling the airplane mode toggle switch on/off 4-5 times to restore carrier signal, AND IT WORKED! I relayed the message to my out of town wife and after trying it, she texted me with the good news. I hope this might help someone else.

When I did the iOS4 update to my wife's 3GS, the phone was in airplane mode. My phone was not and updated without issues. Could this be the culprit ?