@TP-Link 

It looks like my supplier does not take my problem seriously. In short; I've used the system for a while with 2 nodes without major problems. With 4 nodes it is a completely different story. I'm not pushing the boundaries when it comes to distances. My house is fairly small and the only reason to move to 4 nodes is to enjoy perfect WiFi reception everywhere. After installing the extra nodes I am monitoring the system closely. It fails in both choosing the best source node for communication and choosing the least populated channel to do so. 

This thread is about manual source selection, but this is merely a quick fix (both source and channel choice should be automatic and dynamic). The system is just not very good at doing what it is supposed to. It wasn't when I bought it and after several updates it still isn't. Going through some of the other threads, the problem is not related only to M9. It seems just as bad on other Deco's. My biggest problem is that people who read this will probably make other choices and they should. I bought a (premium prized) TP-link product, it does not function as advertised (not a bit, but not at all), TP-link acknowledges there is a problem, I am still stuck with no solution and I am not offered anything else.

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Not providing an exact ETA of the promising firmware, would give you free choice to decide whether to stay or go for a different brand.

Really? Happy to read that I am free of choice. But for that I have to toss aside an expensive system that isn't very good and is still on the market. For now there is nothing else for me to do than write some reviews about my findings with Deco M9 and my support experience.  

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Thank you very much for your attention so far.

  @Uncle_Martin It looks like tp-link has been taking the option to not allow manual channel change for some reason. Users have requested this feature for a long time in the various version of mesh products. Years actualy asking for this, yet Tp-link still not ackowldge this request.

So, what is the option to the users? Write as much as you can, in social media and 3rd party forums about this. Go to amazon and give low rates and explain why. Until Tp-link understand that this choice has an impact on their business they will do nothing. 

So, lets stop talking and start doing something.

Best

CP