When you find that your Android device—specifically a Sony Xperia—lists in the service menu, it generally indicates a hardware or carrier-level restriction that prevents standard unlocking procedures.
: Open the phone dialer and enter *#*#7378423#*#* . Navigate to Service info > Configuration > Rooting Status . bootloader unlock allowed no to yes
Restart the device and check the service menu again. In some cases, the status immediately flips to . 2. SIM Unlocking the Device When you find that your Android device—specifically a