: Navigate to System Settings > Management (or Advanced Settings ) and look for the Restore Backup or Update option.
The .bin file specifically acts as a modified configuration backup. When uploaded to the router’s management interface, it bypasses factory restrictions to grant and unlock the SIM slot for universal carrier use. How to Use the Unlock File
The file is a configuration or firmware file used to "openline" (unlock) the Zhi Ling Tong (ZLT) P21 4G LTE router
: Some versions can be unlocked without files using a "14-14-14 seconds" reset trick performed on the physical reset button.
