I am a happy user of an unlocked iPhone since mid last year. I own one since they came out in the us during late summer. Since at the time, I was unable to buy the iPhone here in the UK, my only option was to use an unlocked US phone. The method to unlock it I use is the TurboSim method.
It worked perfectly fine until yesterday, when I started to see problems. The phone reports that there is no Sim card installed in the phone. A reboot of the phone solves the problem, but only for a few minutes. You can see the signal disappear several times for a few seconds, just before it reports that there is no Sim card installed again. Removing/reinstalling the Sim/TurboSim cards also has the same effect.
After searching around in different forums, it is becoming more and more certain that the problem is actually not the iPhone or the TurboSIM card, but it seems to be somehow caused by a change on the t-Mobile network. Why do I think that? All of the users reporting the problem are also using T-Mobile. Too much of a coincidence. As one of the users mentions, the problem does seem to have started occurring over the past days, at different “start” times for different users, which could indicate that T-Mobile is actually performing some kind of update on their network which is causing the TurboSim to fail.
I remember that I saw a very similar problem when I was travelling in Europe. Depending on which network I was roaming, I would loose the signal and the phone would report the same “noSim card” error message. I thought at the time that it was just me throwing around the phone too much, causing bad contact between the TurboSIM, the real SIM and the actual phone connectors, but now, I kind of think that it might have been the same problem that we are now experiencing on T-Mobile UK.
Here are some links to forums posts of people reporting the same issue:
bladox.com (TurboSim manufacturers Website Forum)
Update: As mysteriously as the problem started, it has disappeared again. My iPhone is working fine again. Unfortunately that also means that i still have no real idea what caused the problem, although I still expect it to be caused by some change on the T-Mobile network.