To unlock a Sony device:
- Insert a non-supported SIM card into the device and turn it on.
- The message “SIM Network unlock PIN” will appear. Enter the 16-digit network lock code and press Unlock.
- The message “Network unlocked” will appear once the device has been unlocked.
Important note: you can attempt to unlock the device up to 10 times. After 10 unsuccessful attempts, the device will be permanently locked to the original network.
How to Check if your Xperia is hardlocked:
1. Start up the phone and press the Menu key ( ) and Back key ( ) as follows:
2. Pressing Key Sequences: Menu Back Back Menu Back Menu Menu Back
Note: Please make sure the phone has the SIMLOCK option int he service menu when dialing the following:
Also You can check there is counter of wrong code is blocked.
Then Select and then if If X is with Network and it is not 0 you can unlock your phone via unlock code.
However if X is 0 then your phone is hardlocked and unlocking via code is not possible.