The D810R is an older router. If you recently upgraded to VDSL or FTTH (fiber) , the modem part will no longer work – but you can still use it as a router/switch (disable ADSL, use a separate modem or ONU).
: Resolves many of the random DNS failures and PPPoE disconnects common in older stock firmware. tenda d810r firmware update
Choose the downloaded file and click Update . The router will reboot automatically once finished. Do not power off the device during this process. How to Check the Firmware Version on a Tenda N301 The D810R is an older router