I've never downloaded a firmware update to my R7000 router. When I purchased it, the big thing was Genie. Now everything is done through the Nighthawk App. My current firmware is v1.0.8.34. When I check for updates on my app it gives me a 'check firmware error'. I know there is an update to the firmware and i have downloaded it to my desktop, however my user's manual does not cover manual firmware updates. I googled how and it says to connect my computer to my router using an ethernet cable but i can't do that since the router's only ethernet cable is attached to the modem. If i disconnect the modem from the router and connect the router to my computer i won't be able to connect to router via Wi-Fi. Maybe that's my problem - i don't know how to connect to my router via ethernet?
Does your PC have a ethernet port? Can connect the ethernet port to the back of the router then connect to the routers web page to manually update using a web browser.
