A resilient firmware treats security as first-class:
: Supports 4G LTE (Cat4) with speeds up to 150 Mbps download and 50 Mbps upload.
The UI says "File is invalid." Cause: You downloaded firmware for the wrong hardware revision (A1 vs B1) or a corrupted file. Fix: Redownload from the official FTP. Check the MD5 checksum. If you have a B1 unit, look for firmware with "B1" in the filename.