NETGEAR router is not found or is not supported.

That 192.168.0.20 looks wrong.

There are often problems coming back from dd-wrt to stock firmware and it's often difficult to find what you need to do on the dd-wrt forums.

The problem might be dd-wrt leaving conflicting NVRAM settings, you should have set the router back to factory defaults in dd-wrt before loading the firmware.

Even so the NVRAM settings can still conflict requiring they be erased before things will work properly.

I don't know if the Netgear tftp firmware update procedure will also erase NVRAM when the firmware is uploaded, a Netgear person will need to answer that one.

But if it does that could be a way to resolve the problem too.

You could try making sure no other devices are using DHCP assigned addresses by, perhaps, turning them off (so that there won't be a possible duplicate address).

But then the router appears to have an incorrect DHCP address range set so this might not be a problem at all, better to be safe though.

Then set your computer's address manually to one that is in the range 192.168.1.2-254, probably over 200 is better in case there ends up being a duplicate address on the network, as the higher addresses are less likely to be assigned by the DHCP server in the router.

For the subnet mask use 255.255.255.0 , as usual, and the gateway 192.168.1.1, and DNS 192.168.1.1, as it is in the above post.

If the router has an address of 192.168.1.1 (and it appears it does from the above post) then your computer with address 192.168.0.(anything) will not be able to communicate with the router or anything else in the 192.168.1 network. That's the point of setting the address manually.

Then try to connect to 192.168.1.1 in a browser and see if it works.