To help point you toward the right firmware tools and files, could you share a few details?
: Crucial updates to the web interface to prevent unauthorized access and protect user data. Customization and Advanced Features
: Modified firmware can remove the NCK (Network Control Key) lock, allowing the to work with any SIM card globally.
Older firmware versions for ZTE devices have historically been vulnerable to authentication bypasses and remote code execution (RCE). While no major public exploit targets the latest MF79U firmware specifically, the device rarely receives OTA updates, meaning the underlying web server binaries may be years old.
: This usually happens if the firmware lacks the network bands used in your region. Re-flash a version intended for your global region or manually check your APN settings.
n-Track 
