If you are the original owner or the account is in good standing, contact the carrier the phone is locked to (e.g., T-Mobile, AT&T, Vodafone). Request a "Device Unlock Code." They may provide it for free if you meet their criteria.
If successful, the phone will display "SIM Restriction Off" or reboot automatically. Your Nokia 100 is now permanently unlocked and ready to use with any compatible GSM carrier. NOKIA MODEL 100 TYPE RH 130 UNLOCK CODE
Once you have the code, follow these steps: If you are the original owner or the