I ran into the same issue described by bkloppenborg here:
I upgraded the firmware and then waited for the router to restart. No luck and now I'm seeing the same exact symptoms:
- Power Light Blinking
- USB Light On (Solid)
- DMZ light never turns on
- Won't reply to pings over WAN or LAN ports
From the post linked above, I should be able to recover the router using a serial console cable.
Can I use the existing external USB port to console in somehow? Or do I have to open up the router and add a stereo jack and then use a USB TTL cable that plugs into that jack and then plugs into my PC?
Thanks for any help setting me on the right path