AC2600

[Jfreymark]

I just updated firmware and now it doesnt work

[plemans]

What firmware did you install?
What issue are you getting? "doesn't work" doesn't tell us much.

are device connecting but not having internet? Are they not seeing an ssid broadcast? 

Are the led's off? Whats actually happening? 

Did you try a factory reset? push and hold reset for 7-15 seconds while powered on. 

[Jfreymark]

It was a security firmware update.  After reboot it never came back up.  Only  light on was the orange ON light.  Afer trying factory reset if flashes clear.  None of my devices can detect the router.  Tried also power cycle and and unplugging also.  Spent over an hour on phone with tech support.  No luck.  They said someone else would call back within 24 hours but never did.  It worked perfectly until I did the update

[plemans]

Sounds like you ran into a corrupt firmware issue. or something happened while updating it to cause it to corrupt (like power failure/surge)

You can try recoving it with tftp or nmrpflash.  

are you on windows? if so, follow this guide

https://kb.netgear.com/000059634/How-to-upload-firmware-to-a-NETGEAR-router-using-Windows-TFTP

just make sure you enable tftp 

https://www.thewindowsclub.com/enable-tftp-windows-10

and here's a video walk through using a tftp client. Use the built in one for windows 10 though. the video is more of an example of how its done. 

https://www.youtube.com/watch?v=R9DLrLQrpaw

and if that doesn't work, you can try using nmrpflash

https://github.com/jclehner/nmrpflash