In the United States and the EU, carriers are legally required to unlock your device for free once it is paid off and the contract terms are met. AT&T, T-Mobile, and Verizon all offer free unlock portals. This is the safest method.

If your goal is to perform legitimate mobile repairs, you should avoid the risky world of "cracked" software. Here are safer alternatives:

Scouring Reddit communities like r/AndroidQuestions, r/mobilerepair, and XDA Developers reveals a consistent pattern regarding GSMCrackGuru: