AT&T Captivate and T-Mobile Vibrant Galaxy S phones store unlock codes inside
This is funny and awesome at the same time. While also possibly being a bit sad for the carriers.
Phones bought from a carrier are usually locked to that specific carrier, meaning you can’t just pop another SIM in and they’d work. If you choose to do such a thing, the phone will ask you for a NCK, or Network Control Key. Which is something that your carrier may give you under some circumstances (in some countries), or will just flat out refuse to give you.
Which is where countless unlocking sites come in, some pretty shady, some not. Which is where you’d normally go for such a thing, pay a fee, and hope that the unlock code they gave you would work.
Well, this isn’t required if you’ve got a GSM Samsung Galaxy S, including T-Mobile’s Vibrant and AT&T’s Captivate. The always resourceful folks over at XDA Developers have found that these phones actually store their unlock codes in a file that is on the device. And no, said file isn’t easily accessible, but thankfully, a procedure to read it has been found.
Not only will this unlock your device, it will also re-lock it should you need to take it back to your carrier for warranty. Furthermore, you don’t need to root your device for it to work.
But that’s not even the best part. See, if you’ve got a T-Mobile Vibrant and unlock it, you can use it on AT&T and get the added bonus of it actually supporting 3G on AT&T.
The same is sadly not true for AT&T’s Captivate, which only gets EDGE speeds on T-Mobile, but still, if you’re a Vibrant owner and for some reason get fed up with TMo, now you know you can switch to AT&T without having to buy a new phone.