An unlock tool is not a single piece of software. It is a category of solutions that fall into three main types:
Insert a "foreign" SIM card and connect the modem to your PC. The modem dashboard (usually at 192.168.1.1 zte modem unlock tool
Unlocking via NV edit might enable all bands superficially, but the modem’s radio calibration data (stored in the NV) is carrier-specific. After an unlock, you might get 4G but lose LTE-A or VoLTE functionality. An unlock tool is not a single piece of software