This is a translation from: ¿LibreROuterOS hace mesh en 2.4ghz? ¿Puede hacerlo?
By default the LibreRouter will only mesh in 5GHz. This makes much sense in the LibreRouter as the 2.4GHz interfaces are used to connect end user devices, while the 5.8Ghz is used as a mesh backbone, preventing them from competing with the clients and that can generate instability problems to the entire network.
Still, you can enable it by configuring it over ssh.
To mesh in all interfaces (2.4 and 5) you have to edit the
/etc/config/lime-community file and have the following in the wifi section:
config lime wifi list modes 'ap' list modes 'apname' list modes 'ieee80211s'
after editting, you need to run
lime-apply, and then reboot.
This information will be replicated in new nodes that get setted up with the firstbootwizard, but you will have to do it for each node that is already installed.