Ensure your router and computer are plugged into a reliable power source. A power failure during the update process can permanently damage the router.
There are three methods to update: Web GUI (easiest), Web GUI with Internet (automatic), and Emergency Recovery (for bricked devices). D-link Dwr-m920 Firmware Update
If LTE connectivity drops after an update: Ensure your router and computer are plugged into
payload promised to fix "stability issues" and "security vulnerabilities". The Point of No Return Leo hovered his cursor over the button. A warning flashed: Do not power off the device during the process. Web GUI with Internet (automatic)