@TP-Link 

thanks for the quick response. I have not tried to replace the two deco M4 wirelessly operating but since the firmware is the same I thought they were identical. the network optimization tells me that everything is perfect but nothing changes ... at the moment I managed to get to connect the farthest Deco to the nearest one but to do this I had to place it in a point where it cannot connect to the farthest one but it's a temporary solution and I don't cover a part of the house (the last one was placed in a remote corner). I read in the forum that is coming a new firmware (1.6?) for M4 that will allow you to choose the connection source between the Deco and to bind a device to a Deco and I think I can wait with this temporary solution. I hope this update arrives soon! thank you for your support and have a good day. Fabio 

@Fabio25 

Meanwhile, there could be a workaround. As far as I know, when Satellite Deco connects to somewhere, it does not try to reconnect elsewhere, unless:

1) There was power outage, or it were unplugged, which forced it to restart;

2) Deco to which this Satellite Deco is connected went down (was powered off);

3) Signal between Satellite Deco and Deco it is connected to became very weak or disappeared;

4) You ran network optimization.

So, based on this knowledge, you can try the following: power off Deco to which you do not want your problematic Satellite Deco to be connected. Satellite Deco will reconnect to a different one. If this is also not the right one, power it off, too. Satellite Deco will be forced to connect to different Deco it sees.

When you got your problematic Satellite Deco connected to where you want it to, power on Deco nodes your powered off.

This setup should stay as is until one of the above happens.

Give it a try.

@Alexandre. 

thanks for your help. I have already tried but the Deco in the middle acting as a bridge to the last one connects with the Deco which is placed even further away or the connections keep on connecting and losing the signal. it is sufficient that the farthest one finds even for a second a distant Deco and it bonds with it, not dissolving until a complete restart. unfortunately it is necessary to be able to select the deco source manually. it does not have to be mandatory, so they can also work automatically for the normale users who do not want to use the manual choice but the possibility of manual configuration or coupling to the Deco with the best signal is really necessary... as well as being able to choose to manually tie the devices to the Deco. for example the samsung tv 75q90r keeps on connecting to the main Deco which is much further away than a secondary Deco which is placed very near... Sorry for my english but I'm writing from my phone which Is setted on italian language

Fabio25 wrote

@Alexandre. 

the samsung tv 75q90r keeps on connecting to the main Deco which is much further away than a secondary Deco which is placed very near... 

@Fabio25 

Your TV model has Ethernet port, according to specs on Samsung web site. If Secondary Deco already placed near, just move it to the TV stand, so that you can connect your Samsung TV to Deco with Ethernet cable.

Whatever TP-Link does in Deco to convince device connect to the nearest Deco, if such device does not know or does not care, it won't work. With my Smart TV, I just connected it to my Satellite Deco with Ethernet cable, and couldn't be happier.

@Alexandre.  Ethernet port on TV is 100 Megabit only, but Yes it comes with enough bandwith even when streaming movies form Nas, but TV Wifi is AC and I would like to use it. Perhaps when TV is connected with Ethernet It doesn't fully comply with Alexa and vocal commands. I have a soundbar and Nvidia shield in the same place which do always connect to the nearest Deco, only TV keeps on connecting to the farthest Deco, even if I don't select mesh function on Deco app (it is strange, I know).