Input the Code: Once you insert a SIM card from a different "unsupported" carrier, the device interface will prompt you for the "SIM Network Unlock PIN." Can You Use a Free Calculator?

If free calculators are failing or seem untrustworthy, there are two primary ways to safely obtain your 16-digit code:

Open a web browser and go to http://192.168.0.1 (default login is usually admin/admin). A prompt will appear asking for the "Unlock Code" or "NCK."