Using https://openwrt.org/docs/guide-user/network/wifi/atheroswds I setup an Archer C7 as main access point and an Archer C6U as WiFi repeater. It works fine each time I unplug it from the mains and plug it back on. However, every time I reboot the router, either from LuCI or command line, the repeater does not "reconnect" itself to the main router and I have to unplug it again.
Could you please help me with any idea where should I start looking?
There are some current issues with WDS. You could try 21.02_rc3. WDS worked for me with that release.
Thanks a lot Chad! Unfortunately will not be able to travel back to the location where the setup above is installed for probably 6 months or more; and I would like to avoid changing things that could break the connectivity. Temporarily (6 months or more) I end-up installing a wire between the two devices, both ends in the LAN ports. Many thanks!