After looking at the docs you linked, I’m not sure why you’d need to bridge the wifi to the LAN - it already is via the inbuilt switch ports (it’s been a while but when I tinkered with WRT it was for consumer wireless routers, which are a router, a switch, and a wireless access point rolled into one.).
Just disable DHCP, DNS, and connect one of the network ports (NOT the uplink) to the network that Router A is on, and Bob’s your uncle. (
The switch part will provide all the bridging (since that’s what switches do) and the wireless is already bridged to that switch.
So I don’t even see a need for relayd software and it’s config. The router, with DHCP and DNS off, the uplink port not used, is essentially just being a switching bridge. If you can disable the uplink port that would be even better, but so long as it’s set to use DHCP for an address, it’ll never get one. Or you could set it to a private class that you won’t use: say your network is 192.168.x.x, set the uplink to use 10.0.0.x. You’ll never have traffic wanting to use that network.
Edit: Ah, I see. You’re using 2 wifi access points as a bridge to each other. Hmm, yea, that’s not typically a thing (though I’ve seen it more recently) which is why you’re using relayd.
Definitely looks like relayd is playing pretend at bridging somehow, but not perfectly. Is there a forum for relayd?