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I have updated iphone from ios 4.3 to 5.0.1. After updating ios, the phone doesn't recognize sim and keep saying sim invalid. However there is no problem with sim and phone never been hacked (jailbroken).
Yes I have, they asked me to send it to Apple as out of warranty..it was working fine on 4.3, I shouldn't have updated it :(
We know there is no problem with sim, but did you try another one?
If you did, try restoring again, may be using another computer. Or same, buy disable your antivirus.
I would try that before shelling out OOW price.

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