Hello. I know how the title sounds but bear with me please, I have tested this multiple times and had the same result every time. I have 4x AX10 routers connected between them with ethernet cables as shown in the picture (the black line is the cable and I also wrote the approximate distance between the routers):

#1 is the main router

#2, #3 and #4 are satellite routers

Until recently I had only routers #1, #2 and #3, all inside the house and everything was OK, they were always using ethernet backhaul for the EasyMesh. However, after adding the #4 router, the EasyMesh network started failing as follows:

• #4 is outside in the garden and is connected to #1 through a 50 meters long CAT5E cable, but when I start the #4 router it initializes using Wi-Fi backhaul directly with low signal connectivity (obviously since being very far) instead of it using Ethernet backhaul, so I get only ~50Mbps due to the Wi-Fi backhaul
• if however I move the #4 router inside the house near router #1, when router #4 starts it initializes directly using the ethernet backhaul (Wired 1000Mbps EasyMesh connectivity shown in admin page) as expected, WHILE USING THE SAME 50 meters long cable, only difference being the routers are now next to each other
• I even tried putting the #4 router next to the #2 router and connecting them using the same 50 meters cable and same thing: it uses the ethernet backhaul successfuly
• when I move the router back outside and restart it, it once again initializes using Wi-Fi backhaul
• The cable is NOT the problem, as mentioned I did multiple tests and I get ethernet backhaul with Wired 1000Mbps when the #4 router is nearby the other routers

A hack I discovered: when the #4 router is outside, far from the other routers, and I am on the Wi-Fi backhaul: if I press the WPS button on the #4 router, the #4 router switches to Ethernet backhaul successfully and shows me Wired 1000Mbps EasyMesh connectivity (this is probably due to the router Wi-Fi being shortly disconnected due to me pushing the WPS button so the Wi-Fi backhaul is cancelled ...???). However if/when the power goes out/comes back and the router restarts, it's back to Wi-Fi backhaul and have to manually press the WPS button again to get the Wired 1000Mbps.

Second problem: after adding this #4 router and doing the WPS hack to get Ethernet backhaul @ Wired 1000Mbps for the #4 router, now router #2 also started failing and switching to Wi-Fi backhaul with low signal (I can only assume it is trying to connect to router #4 - which is far away - using Wi-Fi backhaul for some unknown reason, even though it would be able to use Ethernet backhaul successfully):

If I were to guess I would say there is some logic fail somewhere in the backhaul selection in the firmware, something like "if Wi-Fi signal is low then use Wi-Fi backhaul" instead of "if Wi-Fi signal is strong then try to use Wi-Fi backhaul"...

How do I solve this problem?

Is there any way to COMPLETELY disable Wi-Fi backhaul? It's useless and just causes more problems. Some custom firmware? Or just give me the firmware source and I'll modify it myself to remove the useless Wi-Fi backhaul.