Reliable, fast, user-friendly, supports thousands of models. Cons: Paid credits are required for most ZTE devices. 2. ZTE NCK Code Calculator
Use this method if your ZTE device asks for a code when you change the SIM card.
The process of unlocking targets the modem's software, not its hardware. This means it is generally safe and, contrary to some myths, does not cause your modem's internet speed to slow down.
(Professional/Commercial)
The Ultimate Guide to ZTE Modem Unlock Tools: How to Free Your Device
Use a trusted online ZTE code calculator or software tool to input your IMEI and generate the NCK (Network Control Key).