Ok, I'm very n00bish when it comes to upgrading/unlocking & so forth but here's my question. I purchased a week 41 iPhone from my at&t store. Used it regularly activated under my account for about a couple weeks until I decided to upgrade it to 1.1.1 then jailbreak it. When 1.1.2 arrived I accidently upgraded to it causing the phone to go back to normal specs.

Fast forward.. I then use the steps provided on this forum to downgrade to 1.1.1, unlock the phone using ANYsim then upgrading to 1.1.2 finally jailbreaking the phone. My weird thing is when I remove my SIM card from the phone & put in another at&t SIM card (for example) the phone remains available to use the apps including WiFi however I have no available phone service.

My question would be is it due to the fact it was upgraded to 1.1.2 therefore I cannot use any other SIM card? I ask because I may decide to use my phone while on vacation with another SIM card plus if I decide to sell it later I'm sure I can get top dollar for it. Any help appreciated.