I have 3 M4R Deco`s connected in router mode. The main deco is connected thru a switch to my zyxel router with a cable The two other deco`s connect with wifi to the main deco. The one upstairs has...

@Solla-topee thank you,this helped,i got it connected.

I recently installed a Deco M4 network but stil have a smal deadspot in my garage. I also have a spare TL-WA 854RE range extender,is it possible to connect that to my Deco M4 network?