I have an iPhone 3G running 3.0.
I had some issues with my phone so I did a restore.
I used a computer that did not ever have iTunes loaded to it. I then installed iTunes (latest version).
Based on what I was reading on various forums I did the following:
I inserted an old AT&T SIM from before I was with TMobile.
When doing the restore I entered DFU mode. Then I restored by hitting shift key (pc) and selecting the 3.0 firmware.
After the restore was complete I made sure to enter to airplane mode.
Then I jailbroke the phone using redsn0w 0.8 (windows).
I installed cydia during the jailbreak.
Then I took out the AT&T SIM. I turned off airplane mode and then I opened cydia with no SIM. I then installed ultrasn0w 0.91-1 to unlock the phone.
I rebooted the phone. After the reboot I turned on airplane mode again and then turned off the phone. Then while the phone was off I inserted the TMobile SIM card and turned on the phone. The phone still in airplane mode booted up fine.
I then turned off airplane mode the dreaded message came up..."Different SIM Detected...please connect to iTunes".
I am pulling my hair out...WHAT CAN I DO TO FIX THIS ISSUE?