If you have exhausted all free methods and need a professional solution, the current industry standard for this model is:

When the IMEI is corrupted, your phone shows "Emergency Calls Only" or "No Service."

. They can reload the official stock operating system and restore your original IMEI using proprietary tools. Professional Flashing Tools : Specialized hardware/software tools like Pandora Box

Before diving into the tools, it is essential to understand what the IMEI (International Mobile Equipment Identity) is. Think of the IMEI as your phone’s social security number or fingerprint. It is a unique 15-digit code assigned to every mobile device.

Some users attempt to access the device’s internal "Engineer Mode" via secret dialer codes to manually input IMEI data, though this is increasingly difficult on newer Android versions. Critical Considerations: Ethics and Legality