Using tools like QPST or specialized ZTE firmware flasher tools, the carrier-customized software on the modem is overwritten with the original factory firmware from ZTE.
You enter your IMEI into a calculator software. zte modem unlock tool
If the tool generates a code, open your browser, navigate to the modem's web management page (usually 192.168.0.1 or 192.168.1.1 ), and enter the code into the prompt. Using tools like QPST or specialized ZTE firmware