@Lysefjord 

Please clarify how you connected Deco to each other. For screenshot you shared to make sense, there are two options:

A) You have them connected through the switch:

B) You have them conected the way is called daisy chain: 

Which one of these in your Deco mesh: A or B?

-----------------

This is what your diagram says:

Habitacion connects to Salon over WiFi, with very poor WiFi connection

Sotano connects to Habitacion over Ethernet

Salon is Main Deco, Habitacion and Sotano are Satellite Deco

  @Alexandre. thanks a lot for your answer!

Yes I think that is the problem I have. Currently I have my main Deco connected to the router, then a switch to the same router that connects with the other 2 decos as per image bellow.

I have seen that if I change the opperation mode to AP all seem to work with an Ethernet connection, but doing so I will lose some funtionalities from the TP app. 

I could try to replicate figure A, but I have only 2 ethernet cables coming from the existing router room to the living room and one is used for the TV. I kind of dont like the idea of putting a switch in the living room with all the blinking lights... 

Do you recommend using Deco as the main router or if I go with the AP mode it is fine too? Also If I go with your A chart option, should I change my existing router to bridge mode or it would be sufficient to disable the wifi?

Thanks!

  @Lysefjord 

The way you connected Deco units together will not work in Deco mesh "Router" mode. It will work in "Access Point" mode, just like you found.

You need to decide if you want to keep Deco mesh in Router mode - and rewire Decos to make it work, or switch to Access Point mode.

Also, see this document: General questions about Ethernet Backhaul feature on your Deco

  @Alexandre. Thanks Alexandre! I rewired yesterday and it all seems to be working fine in router mode! 

Now, is it recommended to configure my "modem/main router" as a bridge or not needed?

Tx!