I have a TP-Link TL-WR1043ND v1 with OpenWRT running. I've run this sucessfully for a long time. I also just got an Archer c7, downloaded the recommended firmware, and I have no internet. I've tried power cycling the modem and router in different order, and I have checked Luci on both the old and new routers to confirm that the settings are identical. I even manually entered all my LAN devices' MAC and IP addresses, for static leases, and set up the same port forwarding rules. So from what I can see, the config is the same on both routers, but one gets internet and the other doesn't.
When I look at my overview on the new router, it always says that there are no active DHCP leases, even from the computer from which I'm accessing Luci. And yet, under routers / ARP, I can see that it has picked up a couple static LAN IPs and I can ssh to another machine on my LAN. So I'm not sure why WAN isn't working. Any thoughts?