Use any SIM card from any mobile carrier worldwide.
The is a program—available as both offline software and online scripts—that uses a device’s unique 15-digit IMEI number to calculate specific security keys. These keys allow users to:
Enter the IMEI into a tool like the Universal MasterCode or an online calculator.
The software relies on various "algorithms" (New Algo vs. Old Algo) developed by Huawei over the years to protect their hardware.