@Janu_22 I don't think that will always work. If your Deco unit is turned off, it will try to connect to the main unit again when it is turned on.

  @MackPhoenix62 EDITED: Ahhh finally I can select signal source after upgrading to the 1.6 beta firmware! And it works.

Same issue here ! How can a issue like this not be fixed for 3 years tplink ? I just bought a set for my grandma ( I run amplify and this is not an issue there ) But it keeps connecting all the slaves to the main deco. Running 1.5.4...

@TP-LINK

Not sure if it's been released for M9 PLUS, but would someone mind sending me the beta download for 1.6?  Dealing with the same issue as others have experienced and would love to be able to select source unit.  I currently have 4 in my house - all of which are pointed to the one unit downstairs.

Thank you!

@TP-Link 

I would also like the beta firmware for the P9 units please. 

When i try and ser the source on the M5 I get an error saying failed to save your settings try again later. 

@Tp-link

I thought I was going mad until I found this thread!

I've just replaced my three Deco M5 devices with M9 Plus (not a particularly cheap option) to resolve an issue where one device got such a weak source signal that it was only providing 2.4Ghz while all the others were dual, which casued WiFi calls to cut out as I walked between rooms.

The M9's have resolved this issue but the problem with the furthest Deco receiving source from the main unit, rather than a closer, stronger signalled device is still there. To be honest, if the M5s didn't have this problem I probably wouldn't have had the drop-out issues and would have saved myself a decent wedge of cash resolving with the M9s!

It makes a difference too! My download speeds differ between the furthest from source, receiving a weak signal, and one closer, receivcing a strong one.

Come on @TP-Link ...

It's completely bonkers that this hasn't been sorted since being raised in 2019 and the solution seems simple enough, allow the user to override the source device!!

If you're going to sell a product advertised as MESH, make sure it works as a MESH

- it's a close call whether this could be classed as violating the trade descriptions act!!

I think that I am giving up with TP Link. A firmware update to enable me to select how the nodes talk to each other is a long way off. I am considering upgrading to a Netgear Orbi WIFI 6 or 6E mesh system. Does anyone know whether it is possible to force a Orbi satellite to connect directly to another satellite (as oposed to the main node) or will I have the same issue as with the M9 Plus?

I just got 1.6.0 update to all my M5's (3 x v1 and 1 x v3) and I can now select the source in the app. 

There's been some other updates, but that's the main one I've been waiting for

  @TonyReilly Confirmed! I was able to select the signal source now!

Unfortunately, no such luck for the Deco M9 Plus!!