Odd TP-Link HS110 Smart Plug Behaviour

I’ve got a number of the HS110 Smart Plugs from TP-Link and they were all working fine until fairly recently.

I’ve now got to a situation where one of them just fails to be detected by HA even though it has a static IP. The device itself appears in the Kasa App and I can power it off and on with that with no issues, but HA just fails to discover it.

It looks like i’m running different versions of the hardware though so i’m wondering if that could be the cause of my issue.

This is what I have:

Not Working
Model: HS110
Hardware: 4.1
Firmware: 1.1.0

Working
HS110
Hardware: 2.1
Firmware: 1.5.10

Working
HS110
Hardware: 2.1
Firmware: 1.5.10

Working
HS110
Hardware: 4.1
Firmware: 1.0.4

The combination makes me think it could be something to do with the firmware, but interestingly if I try to use the app to update firmware it doesn’t list any upgrades. Given that I have two plugs with hardware revision 4.1 and one of those is on an older firmware i’d expect the bottom one (currently on 1.0.4) to show as needing an upgrade.

Another interesting quirk is that if I go into the device information for this smart plug it shows the Time Zone as America/Dawson despite this being a UK version of the HS110 (it’s actually printed on the back of the plug).

Does anyone have any clues on why HA might not be detected it or if there is any means to downgrade the firmware?

Thanks

Pete

@Peter_West - there was a recent release of firmware for the 4.1 hardware that has killed local connections to the devices and prevents the current HA implementation working. It is thought that this related to a recent Which Mag security warning and so TP-Link are pushing out firmware changes. You may be lucky on the working HS110 that it is not auto updating as it is looking at the wrong country.

Thanks @quenchmaster

The fact that none of my other plugs will update to that firmware makes me think that maybe they’ve pulled it.

I’ve opened a support ticket with TP-Link for now to see what they say. Functionally it works fine in the Kasa App so i’ve flagged with them that the incorrect time zone is what i’m complaining about. I guess i’ll see what they come back with. I’ve also asked if they can explain why the other 4.1 device I have appears to be stuck at firmware 1.0.4.

Pete

I noted a few days ago that some of my HS110s had stopped working when I was controlling them via anything other than the Kasa app, I used Node Red to write a home automation system and it has worked perfectly with the HS110s for over a year.

At first I thought the issue was with the code I was using to interact with them but I then tried a few alternative open source solutions to connect to the HS110s and in every case I got the same result.

I then started to look at which HS110s were working and I noted that all my ‘hardware version 4.1’ plugs have stopped working but all my ‘hardware version 1.0’ are working fine.

I have about 10 plugs and they all follow this same pattern so it looks as if the issue relates to the specific hardware version. All of my hardware 4.1 plugs are on firmware 1.10.

I don’t have a solution yet but this is the only place I’ve found so far where people seem to be experiencing the same so I thought I’d post what I know so far.

I just port scanned a working and a not working plug.

The working plug has port 9999 open which from my reading is used for local control.

The plug which is not working does not respond on port 9999.

This suggests (as others have said above) that an updated firmware has blocked local access. I also found the Which? article and their analysis was that all local network users can control and access the plugs.

I suspect that TP-Link will not see fixing access on port 9999 as important as I suspect a tiny proportion of their customers use the plugs in that way (I hope I am wrong though). I am going to look to see if there is a way to manually install a specific firmware version but I don’t hold out much hope.

I am also going to see if TP-Link have ever mentioned local access as a feature of the HS110, if they have then it would be useful in trying to push them to re-enable port 9999 or get refunds.

Which - https://www.which.co.uk/news/2020/10/cheap-smart-plugs-could-expose-you-to-hackers-or-even-cause-a-fire/
Analysis of open ports - https://www.softscheck.com/en/reverse-engineering-tp-link-hs110/

Last post for now, reply from TP-Link from a githug thread with lots of details…

"Thank you very much for your email requesting information about TP-Link product.

We were aware that there were some security vulnerability on the previous firmware, some third parties might take advantage of the vulnerability to manage the plug. To avoid the potential attacks and security risks causing by this, we have released a new firmware version 1.1.0 to fix it. After upgrading to the latest firmware, some customers who were not using KASA app to manage the plug might found that it is not working.

It is suggested to use the TP-Link official App KASA to manage the plug, and we can confirm that there are no functionalities on the KASA app have been removed on the latest firmware. Your understanding will be much appreciated."

Github link - https://github.com/home-assistant/core/issues/43088

HS100 UK units with h/w ver 4.1: New firmware 1.1.1 received this morning - it works!!!

Yes, I also happened to update mine this morning and everything is back to how it was before.

Nice!!