The International Mobile Equipment Identity (IMEI) is a 15-digit unique identifier assigned to every mobile device

Which of those would you like?

Risk of Bricking: Attempting to alter these core identifiers can permanently damage the phone’s communication hardware, leading to a "No Service" or "Invalid SIM" state that cannot be fixed. Essential Nokia 130 Secret Codes

Original IMEI Recovery: Rather than "changing" the IMEI to a random number, the suite queries a secure hardware fuse (eFuse) on the motherboard. If the original IMEI has been corrupted in the software layer, this tool restores the factory-default identity stored in the hardware's read-only memory.

Unlocking carrier restrictions — This is legal and can be done with an unlock code obtained from your carrier or a reputable third-party service (not by changing IMEI).