Specific hashes that vary by carrier and region.
ZTE’s older dongles (pre-2015) used a relatively simple XOR-based checksum algorithm. Newer 4G dongles use a more complex method truncated to 16 decimal digits. The process looks like this: zte modem dongle unlock code calculator -16 digit-
Coders discovered the algorithm involved mapping the first 15 IMEI digits, summing them, and performing Modulo 10 operations to generate each of the 16 digits. Specific hashes that vary by carrier and region