@Mark_Deco-M9v.2 

So for other people looking to update firmware on their DECO M9 - start from the lower level Firmware update, seems that I was missing 2 and couldn't skip 1. After the first one was installed, the second (latest firmware 1.4.3) became available to install via App.

This doesn't mean the problems are over and ill keep monitoring if the drops continue since the issues started randomly - everything was fine for few weeks :)

Hoping for the best

EDIT: Hope was short-lived - same thing is still happening, 2 minutes, noticed that website is not loading. The red light was on and yeah, no difference!

@Alexandre. 

Hey, so I did another test and added the old TP-Link WiFi router after the modem and connected the Deco M9 Main unit behind it and set it up as AP and 5 minutes in things seem to work. I mean webpages load instantly, not take 10-15sec to start loading. Speedtest also works, one thing I noticed - after all the FW updates, etc, my main unit speed is down from 120Mbps to 70-80Mbps 

I hope it's just some odd tests, not the FW making some odd optimizations. 

Okay, to go over the point, then somehow it works in AP, but this is not what I want - to have yet another module in the network (it is also WiFI so it will interfere with Deco M9 also)

Secondly - why did the problem start today? And I can't turn it back? 

Also, I'm anxious to know how long this patched up odd thing will work for :/...

EDIT: Sorry, I just have run so many texts, that I wanna point out all my findings - When I updated the FW, what I noticed was that IPTV now started lagging - It feels like its having a hard time communicating or translating the modem. But the old TP-Link WiFi router seems to be able to communicate with the modem just fine, just like the Deco M9 did before.

Anyone from TP-link support here? Maybe someone could take a look into it?

@Mark_Deco-M9v.2 

Agreed: it is time for TP-Link Support to join the conversation.

If you plan to keep Deco in AP mode for now, I suggest you turn off WiFi on your TP-Link router. You are correct, you don't need another WiFi network interference. By doing that, you'll make TP-Link router manage your network and Deco manage your WiFi signal.

Answering your previous question, I run pair of Deco M9+ in AP mode for last 3 weeks, since I bought them, with no such issues whatsoever. On initial setup they auto-upgraded to firmware 1.4, and they are V2.

@Alexandre. 

Well, again it seems I was cheering too early. Red light is appearing again, 2 in the last 5 minutes. Initial 20 minutes all worked awesomely, then IPTV started to slow down and now back to red lights...

I'm out of ideas as of now. I'm thinking of hard resetting the outdoors modem to see if this helps