With EMUI 5.x and 8.x (Android 7-8), Huawei introduced a server-side salt. The unlock code was no longer purely device-generated. The v3 algorithm required a specific challenge-response handshake. The new algo v3 calculators simulate this handshake offline by reverse-engineering the server’s token generation.
If "V3" fails, try the "New Algo" (V4) option for better results. Works for most Huawei E-series modems and B-series routers. With EMUI 5