Bought this f7d8301 router on ebay used. Wouldn't connect to the WAN with the original firmware. Thought tomato might fix that problem but same. I'm using a cable modem and I have the connection type set to DHCP. In status it simply says "Renewing…."
is it possible to change one of the LAN ports to wan?
Yes. I think you can do it in the GUI. If not the GUI then command lines can. I don't have that build installed anywhere but you should be able to Google it.
Figured out how to change the WAN port to the original LAN 4 port, but i still get the same problem. Under the "Ethernet Ports State" on the overview page it recognizes that the cable modem is plugged into the WAN port (original LAN 4 port) but the status says "Renewing" and never changes.
Is it possible that there is not a hardware malfunction that is causing this?
I had two identical routers once. Two e1550. They both had the same exact Toastman firmware. One of the wouldn't talk to a particular cable modem, the other did just fine. Both worked with some DSL modems I have. For some reason, that particular router and that particular modem would not talk. Everywhere else they would work. Try out some different modems, like at a friends house or something if you can. If none of them work with your router, it's probably the router then.