This Android app contains advice and suggestions for unlocking your PUK codes.

When a personal identification number is lost or forgotten, a SIM card's Personal Unblocking Key, also known as PUK or Personal Unblocking Code, is used to reset the number. PIN protection is a function that is available on the majority of mobile phones.

It refers to an 8-digit code that is specific to your SIM card. You could use your PUK code to unlock your device and reset your SIM PIN if you don't know it. PUK codes are used to unlock SIM cards that have been blocked after three incorrect PIN entry attempts. A card that has been blocked by the PUK code cannot be unblocked; it can no longer be used and must be replaced.