Final update (I hope). I've now reverted to using my ISP-provided router and connected this to the Fibre ONT box. I then factory reset all Decos, and re-connected one by one; but instead now just...

Ok, I think I've had the longest period of success now. Previously, my first "Unmanaged switch" was a D-Link and the second one was a TP-Link. I changed over the D-Link one now to a TP-Link LS1008G....

So I took away all switches and am now just using one 5-port TP-Link switch to supply the two satellite nodes. So far so good (again) but as usual this takes a few days to see if it is stable.

Well I'm back to square one today / over the last 24 hours. I've lost ethernet backhaul again suddenly. I know if I go factory resetting again and connecting one-by-one it will probably work. I think...

Found a Youtube Video showing a easy guide on how to use these. Turns out the cable is fine (the legacy one connecting Deco 4). The only thing I can thing of now is that I had another ethernet cable...

Ok, some progress I think. I was able to find that by plugging in Deco 4 (in Diagram) via ethernet to the Switch, was causing Deco 2 and 3 to start their red lights flashing. When I plugged it out,...