Trouble with carrier unlock

[ben824]

I unlocked a 3GS and sold it last week. I unlocked it through AT&T as I had done with a few other iPhones and that went well. Sold the iPhone and the person I sold it to said their SIM Card is not being accepted but the phone (yes it is the right size and it is on a GSM network). It keeps saying no SIM Card detected. Now all the other iPhones I had sold were almost instantly unlocked. This one keeps having issues. I instructed the buyer how to put the phone into DFU mode and do a full restore and it still isn't working.

Now AT&T says it can take up to 7 days. Has anyone actually had it take that long?

 

[617aircav]

You should have made sure it was actually unlocked before selling it.

 

[PsstGreek]

Does the 3GS you sold have the iPad baseband on it?

 

[ben824]

You should have made sure it was actually unlocked before selling it.

When I acquired it, it had a T-Mobile SIM card in it but would not go past the Apple logo upon start up. I did a DFU restore and got it to boot to the startup screen as a new phone. I assumed based on the fact it had a T-Mobile SIM card that it was unlocked. Likely I realize now it was probably a jailbreak unlock.

 

[ben824]

Does the 3GS you sold have the iPad baseband on it?

Not sure. How could I find out and what would kind of affect would this have or not have?

 

[sammy-boy]

Could it be the phone has developed a SIM card reader fault? Or the seller's SIM is a slightly dirty?

 

[PsstGreek]

Not sure. How could I find out and what would kind of affect would this have or not have?

The new owner would have to tell you. The modem firmware (baseband) would be shown in the about settings - 6.15.00

The factory unlock wouldn't work properly if the baseband is altered to the iPad one.