FAQ: The update doesn't update - ntadmin/DGND3700v2 GitHub Wiki

Whilst there is no reason for the update to not be accepted and work that we know of (unless you have installed version from around NEWT16B4 despite the warnings), it has been observed that:

• Sometimes, it just doesn't complete. Try again.
• If the router is running as a router linked to a modem by PPPoE, the update often doesn't complete. (See here). The solution is to unplug the PPPoE line, wait a minute or two and then do the update. However, if this fails, when the machine reboots, don't plug the PPPoE line back in. Simply try the update again. This often resolves it.