So I have Archer C7 V2. I have recently bricked it then just managed to fix it again today and re-flash it with OpenWrt 18.06.1 (same version I had before I bricked it with a different firmware).
Earlier I had WAN not working (probably incorrectly set-up). Now it's working, and I can in fact ping form the router, but not form the PC. I am confident that the modem is properly set-up, as it's working with a different router running a different firmware (and again I can ping form openwrt).
The modem is actually modem-router set in bridge mode, and connected via Ethernet cable to the WAN port of Archer C7. I tried setting the LAN address of the modem is on 192.168.0.1 (not that I expected it will fix the problem), but still, computers connected to the router have no internet. It doesn't seem to be DNS issue either, as I tried pinging 220.127.116.11 from the computer but no good.
Attached screenshots. Is there anything wrong there? I noticed that the WAN port got no MAC address, but I don't know what that means.