Jail breaking iPhone3GS permanently changes it?

[captainbdsc]

I have an old iPhone3GS given to me by a friend. It was jailbroken previously, but has been officially unlocked in AT&T's system. I have factory restored it (plugged into computer while holding the button) but it won't see my T-Mobile SIM card. It just says, no SIM card is installed. After browsing the web for a while I read somewhere if it was jailbroken it can permanently mess with the phone. Is that true? Is that why it won't recognize the SIM? If I got a hold of a AT&T SIM card would that make a difference? My friend gave his brother his iPhone4, also unlocked, and it worked just fine. His brother is using it on T-Mobile.

Any ideas?

 

[Massie]

Did you unlock it with AT&T, or were you just told that it was unlocked? Many times people mistake a software unlock for something permanent so that could have happened here. If you want to restore, plug in to iTunes and hit the Restore button. (No need to hold any button on the phone.) Let it restore, then choose Set Up As New Phone and go from there. (Jailbreak is almost certainly not the issue.)

If it wasn't actually unlocked w/AT&T it's not a difficult process to get that done, either.

 

[captainbdsc]

Did you unlock it with AT&T, or were you just told that it was unlocked? Many times people mistake a software unlock for something permanent so that could have happened here. If you want to restore, plug in to iTunes and hit the Restore button. (No need to hold any button on the phone.) Let it restore, then choose Set Up As New Phone and go from there. (Jailbreak is almost certainly not the issue.)

If it wasn't actually unlocked w/AT&T it's not a difficult process to get that done, either.

It was unlocked by my friend via AT&T. He did the same for the iPhone 4 he gave his brother and it worked perfectly.(It also had previously been jail broken.)

Oh? I thought you had to hold down the button while you plug it into iTunes to force it to do an actual factory restore. I will try again.

I cannot do anything with the phone via iTunes unless I power the device off, hold down the main button then plug it into iTunes. Then iTunes sees that the phone is in recovery mode and restores the device to the latest OS and factory settings. However, it still says that there is no SIM card installed. Could it be possible that there is something mechanically wrong with it? I think I saw a youtube video showing that there is some lever or something that tells the device that there is a SIM card installed (working or not). I have looked in as best I could and it appears that all the "prongs" that make contact with the SIM card are there.

Any other ideas?