Basically they add your device ID number to their database of devices that are considered unlocked. Once the device pings the mother ship, your device gets unlocked.
So the phone pings Apple before it connects to ATT or Verizon?
I did this yesterday for my JB iPhone 4 on 5.0.1
Steps:
1. Call at&t and ask to have your out of contract iPhone unlocked. You must provide IMEI.
2. Wait for email from at&t with instructions.
3. Do not follow instructions.
4. Download and run latest Redsn0w.
5. Click 'Jailbreak' (you won't actually be jailbreaking), put phone in DFU mode, and let the tool apply the Limera1n exploit.
6. Uncheck all items except "Deactive". Make sure you do not check 'Install Cydia'.
7. Click 'Next'.
8. Upon reboot, open iTunes to reactive phone and verify unlock.
*Note that the Redsn0w steps may be slightly different if you're on 5.1.1 (e.g. no DFU mode required) but the tool is pretty explicit about this.
Or you can just use SAM to deactivate, then plug it into iTunes and the unlocked banner will pop right up.
Or you can just use SAM to deactivate, then plug it into iTunes and the unlocked banner will pop right up.
So I did this and the "Congratulations, your iPhone has been unlocked" screen is there on my iTunes screen. Under the "Congrats..." message it says "To set up and sync this iPhone, click Continue". Assuming I don't want to restore, should I click on "Continue" or just disconnect my phone from iTunes now?
Yes, doing so does not restore your phone
Thanks very much for the reply. I must admit that I went ahead (before I got your reply) and disconnected my iphone from itunes without clicking on the "Continue..." button and everything seems to be as it should be. I uninstalled ultrasnow from cydia, rebooted my 3gs, removed my original att sim card, installed an active t-mobile sim card, and voila, hooked right up, so the factory unlock is apparently working as should be.
I don't know if I missed anything by not waiting for your response and disconnecting from itunes rather than clicking on the "Continue..." button, but so far so good.
Using SAM to deactivate and then connect to itunes was a real good tip and time saver since I did not have to restore my phone and go through all that hassle. Now I have a 3GS jailbroken with Snowbreeze, factory unlocked, on ios 4.3.3 and modem firmware 05.13.04 with all the stuff I use working just fine.Can't decide if it would be worth it on this phone to upgrade now to ios 5.1.1 and then jb again or not. Thoughts welcome.
Or you can just use SAM to deactivate, then plug it into iTunes and the unlocked banner will pop right up.