[masraum]

Originally Posted by spuggy

Nope. A carrier-locked phone detects a non-carrier SIM inserted and wants a PUK, or it won't use it.

All you do is enter the code, and the phone is SIM unlocked. Forever.

All happens on the phone; nothing is sent from the carrier.

https://en.wikipedia.org/wiki/SIM_lock



Any carrier is obliged to provide the network unlock code if you meet their criteria - which usually hinge on the account/contract being in good standing, past some minimum age - and almost certainly you having paid back what they wanted for the phone, if it was obtained on a subsidized plan.

So, if the contract is lapsed, you've nothing to lose by asking AT&T for the unlock code; I rather doubt they'll provide it. But I haven't used them as a carrier since I binned them in 2005 for abysmal customer service, so what do I know? It may be different now (I would hope os). And it may just depend on the agent you get to talk to as well.

AT&T used to be rather hard work to get a code out of anyway. If they're still the same, it's probably just easier to buy an unlock code on the interwebs for $20.

It's all automatic these days (at least for ATT) whether you are the original purchaser or not. You enter the IMEI your cell and a valid email address, and presumably, their system checks eligibility for unlocking, and then does it. On an iPhone, there's no code. Just stick the new SIM in and go. I don't know if that means that they do it remotely or what.

We approved your unlock request

Unlock instructions:

Using a Non-AT&T SIM Card:

1. Remove your SIM card and insert the new SIM card.

2. Complete the setup process.

Using an AT&T SIM Card:

1. Back up your iPhone.

2. When you have a backup, erase your iPhone.

3. Restore your iPhone from the backup you just made.

Contact Apple support if you have additional questions.

Thanks for choosing us,
AT&T