I actually had the same issue but mine was because I installed the V2 firmware on a V1 and bricked mine.
I had a really hard time getting the original firmware installed but here are the steps that finally worked.
Downloaded the firmware to my laptop and put on the root of C:\
renamed the file to upgrade.bin (just to make it easier to type)
I connected my laptop to port 1 and put my laptop into the network with an IP of 192.168.1.100, subnet mask 255.255.255.0 and gateway 192.168.1.1
I opened 2 command prompt windows.
On the left side of the screen I ran a continuous ping (ping -t 192.168.1.1)
On the right side of the screen I setup a tftp (tftp -i 192.168.1.1 PUT upgrade.bin) at the root (type c:\ and enter to get to root) but don't hit enter yet.
I then plugged in my router, press the reset and hold it. Hold it until you see the ethernet port light turn off, it will be off for like a second or two. This will take somewhere around 45 seconds to a minute. Once I see the ethernet port go out, I let go of the reset and pressed enter on the tftp.
About 10 seconds later I saw the pings were successful and then a bit later I would see the transfer succeed.
Then I reset the router again, but this time just for 30 seconds.
Once that was done, my router was restored completely.
Hope it works for you.
