BD_FLYMODEMMU5001V1.0.0B02 was reported to break the IPv4 stack, causing "restricted network access" errors.
directly on the ZTE Support Download Page to find available firmware packages and user guides. zte mu5001 firmware link
T-Mobile rebrands this as the T-Mobile 5G Hotspot Inseego MiFi X Pro 5G (Note: Inseego is the firmware partner). The correct link is found at: https://www.t-mobile.com/support/devices/5g-hotspots/inseego-mifi-x-pro-5g BD_FLYMODEMMU5001V1
Recent user reports from Reddit suggest that firmware version is buggy. It may cause: though these often vary by region.
: You can check the ZTE Device Support page for any available offline update packages, though these often vary by region.