SOLVED (see last post) ---update---- I called Apple UK and they said this was far from normal. I had to sent my original receipt to verify that I'm the original owner. Then I need to call back in two days with my case number (given by them). They said they could unlock the IMEI number or anything. So. . Let's hope. ------ Hi, In the summer of 2010 I went to the UK to buy a factory unlocked iPhone 4. The iPhone 4 has been used with numerous of different providers and didn't come with a sim at the purchase. The iPhone is bought and used as unlocked. Yesterday I upgraded the iPhone 4 to iOS 4.3 and when it was done this message popped: "The SIM card inserted in this iPhone does not appear to be supported" THIS IS IMPOSSIBLE. So after some reading I figured that iOS 4.3 locked my iPhone 4! Now, it tells me to find a official card to unlock it. But there isn't any. The iPhone came with nothing, it's not provider locked. And I live in The Netherlands, so going to the UK isn't a option. Now, it's basically useless! Are there any suggestions of things I could do? It never crossed my mind that the iPhone could get locked. There's a reason I bought it unlocked, right? *the screenshot is Dutch.