Manufacturers hide the IMEI in a protected partition called the or EFS (Embedded File System) . To change it, you must bypass Qualcomm’s security protocols.
Changing the (International Mobile Equipment Identity) of a device like the ZTE MC801A is a technical process that carries significant legal and functional risks. zte mc801a change imei
Once the diagnostic port is active, tools like DC-Unlocker or ZTE Qualcomm Writer are sometimes used to "repair" a missing or corrupted IMEI by writing a new one to the device's Non-Volatile (NV) memory. Manufacturers hide the IMEI in a protected partition