Hello. I installed a new ZBT-2 on my HA recently. It runs on a Raspberry Pi 3, and I used the original 1,5m long USB cable to connect the ZBT-2 to the R Pi.
I could paired 8 devices from IKEA (doors sensors and presence sensors).
I installed for that the add-on “Matter Server” and “Open Thread Border Router.”
After a couple of days, I saw that the sensors went sometime in a state “unavailable” for a couple of minutes. Then, it occurred more and more, so that the devices are sometime available only 10% of the time. When this hapend, all the devices are set to “unavailable”, at the very same time, but the recovering the devices may happened faster for some devices. Here is a picture:
At night, my wifi is turned of, and the issue still occurred, so I ruled out an interference issue. I guess this problem is not also on the side of the IKEA Hardware, because all devices are displayed as unavailable at the same time. I image this could be a problem with the mater server of the firmware of the ZBT-2.
Does someone already experienced something similar? I don’t even know in which log file I could get some usefull data… Thanks !
After some longer tests and researches, it turned out that the matter server failed from time to time. Looking at the log:
Add-on: Matter Server
Matter WebSocket Server for Home Assistant Matter support.
Add-on version: 8.3.0
You are running the latest version of this add-on.
System: Home Assistant OS 17.1 (aarch64 / raspberrypi3-64)
Home Assistant Core: 2026.3.1
Home Assistant Supervisor: 2026.03.0
Please, share the above information when looking for help
or support in, e.g., GitHub, forums or the Discord chat.
s6-rc: info: service banner successfully started
s6-rc: info: service matter-server: starting
s6-rc: info: service matter-server successfully started
s6-rc: info: service legacy-services: starting
s6-rc: info: service legacy-services successfully started
[22:25:39] INFO: Starting Matter Server...
[22:25:42] INFO: Using Python Matter Server
[22:25:48] INFO: Using 'enu1u1u1' as primary network interface.
[22:25:51] INFO: Successfully send discovery information to Home Assistant.
2026-03-15 22:26:26.608 (MainThread) INFO [matter_server.server.stack] Initializing CHIP/Matter Logging...
2026-03-15 22:26:26.645 (MainThread) INFO [matter_server.server.stack] Initializing CHIP/Matter Controller Stack...
[21:26:28] WARNING: matter-server service exited with code 137 (by signal 9).
The last line detail the failure.
From this Post, I concluded that the reason of the regular crashes and therefore the unavailability of the devices are a consequence of a lack of RAM. I am using a
Raspberry Pi 3 B+, 4x 1,4 GHz, 1 GB RAM, and I am now fully out of spec.
