I have an iPhone 3g with firmware 2.2 and baseband 2.28. I have bought two seperate proxy sims to use with my t-mobile sim. Both proxies worked for a few minutes, then lost signal and said "no sim". I have tried 5 different sims in the phone with the same two proxy sims and none of them are recognised. My theory is that something is being stored in the proxy sim which the iPhone is rejecting. My question is, is there any way to reset the proxy sim back to it's original state?