WNDR3700v5 cannot connect access ip in webgui or ping

[o1nk]

OK. Bit of a long story here, but I'll try and add all the info I've done.

Bought a WNDR3700v5 from a car boot sale and it powers up fine. Connect via ethernet to it and can't access routerlogin.net (not in WLAN port)
Add it to my existing network and it works great as a throughput/access point.
Tried to access the ip from Advanced IP Scanner / arp -a / nmap
OK. Tried to hard reset, following all the guides, including 30/30/30 / 7 seconds / Turn it off and hold reset while power back on 45 secs then 15 secs if the power is not flashing
All of these state that the power light must be blinking
My power light comes on after each "reset" but never flashes. The only thing that flashes are the internet and the wifi lights, blinking alternately.
No access to 192.168.0.1,  192.168.1.1, or even routerlogin.net

Plug my ethernet of my network back in and power / internet / wifi lights go off, but as an access point it still works as before.

So I don't know anything about DD-WRT, but it I don't know if it's been flashed with their firmware as;

1) Can't ping it

2) Can't access it on any ip sniffer
3) Can't access on the webgui (different browsers)

So
In short

It works as an access point fine
I cannot reset it to make the power light flash
I cannot ping it either on my network, or in a single laptop config

Anyone got any ideas?

[plemans]

Ideas? It might be why it was sold. 

Without knowing what was done to it and you having already done all the reset procedures, kind of limits you. 

sounds like you've tried most all the fix it procedures.

You could always try tftp or nmrpflash to reinstall the firmware to it. 

You can try recovering 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

[o1nk]

Thanks plemans

I'll give that a go.