It's now 2020 and I still can't tell if powerline backhaul is working. This was promised over a year ago. Any news on when this will be available? Also, how about a method to test the speed of connectivity?

Thanks

@EMerks 

I have the same problem and using telnet to try and fix it just seems crazy.. I'll be sending these back to Amazon, what a waste of time.

"Disconnected from other Decos" seems to be the go to message on theses devices, just because they won't use the power line... my walls are over 30 inches thick!! 

@John55 https://community.tp-link.com/en/home/forum/topic/210648

It seems I can't telnet any longer to the router with the new firmware.

Can anyone do it?

Still no update here in the UK (06/06/2020) :(  Also the Deco app on android isn't working now, keeps erroring and saying the network is disconnected (when it's working perfectly fine!).  The iOS version works fine. I'm trying to upgrade to 1.0.2 beta that's floating about here, but i'm getting a AuthenticationException: Authentication failed. error even though my credentials are correct??

@jpasan any update on this? I've tried but it's not working. Unfortunately I forced the plc but with the new update i can't change it back 

@Chinaa108 

I had no updates on this. The only solution I had was to reset the Decos.

I had to do it actually, as the two satellite lost connectivity to the main Deco 3-4 times with the new firmare and Wifi Backhaul disabled. Since the reset, only once the third deco lost connection to the network, apparently due to Wifi connectity loss. I'm guessing because I see the connection in the app most of the time having two bars, but sometimes going down to one. PLC seems stable, but there's no way to check the speed. Only if it's connected or not.

I don't understand why the Decos insist on WiFi backhaul, forcing a Daisy Chain configuration instead of star one, when PLC is available. Worst, though, is losing connectivity to the network when PLC is available as an alternative.

New feautures to add in my opinion:

- Show PLC connectivity details

- Allow prioritizing backhaul

@jpasan thanks for the reply! Just to confirm, resetting the P9 system most definitely wipes out the changes we made to the /etc/config/WiFi to it's original settings. 
 

I'm having a tough time with the plc on the p9. The TL-WPA4220 plugs I had before worked very well with great speeds. With P9 plc only, I'm getting circa 1.5mbps on Speedtest. 
the TL-WPA4220 were cheaper and better even though they didn't have mesh!

This P9 system is terrible!

Hopefully if they ever update the firmware again, It would be nice  to see the link speeds between the P9 units, so we could place them in optimum places. 

Just joined in order to say a lot of the info is now available, certainly that in the thread title. This is as of 26/07/2020 with latest firmware for the p9. Screenshots below showing how to find it.

Press internet at the top:

Select a deco:

Shows either WiFi or WiFi and PLC. When mine was in a surge protected powerstrip it was WiFi only, but seeing that I moved to the wall socket and I can see it's connected over PLC now:

Firmware version fyi: