just to let you know, the PIN2 is SIM dependant as well.
it is 5678 with TMobile UK.
If you enter it wrong (or it has changed from 567

, it will request a PUK2 from you.
To get this PUK2 code, you need to contact TMobile customer services.
DON'T try to enter PUK or PUK2 yourself as you will end up locking up your SIM, perhaps the device or both!