Netgear nighthawk X6

There's a support site with access to manuals, firmware, install guides, etc.
Go to https://www.netgear.com/support/
Type in your model number and from there it'll take you to the above.

Its a great resource to start with.well you can manually update: 

https://kb.netgear.com/23960/How-do-I-manually-update-the-firmware-on-my-NETGEAR-router

or try the automatic router. 

https://kb.netgear.com/23442/How-do-I-update-the-firmware-on-my-NETGEAR-router-with-a-web-browser