First variant. Concludes the firmware of the router through its web-interface. The firmware file should be downloaded from the web-site of the router manufacturer of this model. When passing by the router model it’s important to pay attention to its version (Ver.) and revision (Rev.) which are specified on the back side of the device.
So as when flashing the router with the wrong revision it can stop working correctly and in this case you will have to resort to other methods.
To enter the router settings you need to know its ip address and login with password. This information is mostly presented on the back side of the router by the vendors.
Then using the LAN cable you need to establish a connection between the computer and the router by connecting one end of the twisted pair to one of the Lan ports.
In some cases it will not be possible to connect by specifying the address of the router in the browser.
It can most often be because the computer has a DHCP connection. Therefore, in the network connection settings you will need to manually write the IP address close to the address of the device itself. (Example 192.168.0.100 if the router address is 192.168.0.1)
Firmware Update Firmware section will remain in the router settings. After that you can start the firmware upgrade by pointing to the file with the new version downloaded from the official site.
The second variant considers essentially easy method of router flashing in automatic mode. That allows to carry out the update process much safer. Unfortunately, not all routers have this feature. For example ZyXel Keenetic Viva has this possibility where in the section of system settings in the tab of updates.
Three variant. In this method, router firmware is implemented in the aggregate of additional hardware and software complex.
Preferably the considered variant is used when it is impossible to enter the router web interface. A detailed review of this method is presented here: