New PI 5 with ZBT-2 can't connect to matter devices

Configuration Matter/Thread
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1

Hello everyone !
I’ve been using HA since March, and it’s been going well so far. My setup was running as a Docker container on a TrueNAS machine, connected to a ZBT-2 for Matter devices pairing always worked fine, no issues.

Due to memory usage constraints and a planned move toward using HA with Frigate, I decided to migrate to a Raspberry Pi 5 (with a Hailo-8 for future Frigate use). I installed HAOS, plugged in the ZBT-2, decommissioned the previous instance, and restored my previous backup. Everything came back correctly, existing devices reconnected fine.

My issue is any new device I try to commission fails. I start pairing, my phone shares the Thread credentials (as usual), it moves to the “checking network connectivity” step, and… nothing. It sits there for a while, then times out and suggests checking Wi-Fi.

So about what I’ve tried:

  • Disabled OTBR Firewall
  • Uninstall & Reinstall OTBR & Matter Add-ons
  • Checking logs (spoiler: I didn’t see anything, like the device is not reaching HA)
  • Create a new Thread Network
  • Ask to Claude (with HA MCP, to read logs, without any success)
  • Clear cache of the companion app & Google Play Services
  • Check for IPV6 (all’s good)
  • Sync Thread identifiers so many times I lost the count
  • Try an antother USB port for the ZBT-2, and an another cable
  • Tested with an Iphone companion app. Same issue.
  • Tested with 2 differents devices (Aqara W600 thermostat, IKEA temp/humidity sensor)

The only option I still have to do, restart a fresh configuration, but I have no guarantee that would actually fix it either.

That’s all folks.
What do you think? Is it ring any bells to someone ?
Even if not, thanks a lot for reading this far and for your support :slight_smile:

Damien

2
  • Running WIFI on a server is not a good idea for one. Expect weirdness if you try compared to an Ethernet link.
  • If you are running any VLAN’s Thread has a lot of trouble with those.
  • There was a requirement a month or so ago to update PI5 eeprom to fix some problem, were you able to complete that?

Just a couple of possibilities off the top of my head.

Possible help with the WIFI thing, not sure… https://developers.home-assistant.io/docs/operating-system/network/
If When you come back for help here, please let the person helping know your server is on WIFI.

3

Ah yes sorry. Didn’t precise… It is not on Wifi, but Ethernet. I am trying to check about eeprom and VLAN, thoses could help.
Thanks

4

[Matter & Thread Deep Dive](https://www.derekseaman.com/2023/10/part-1-smart-home-matter-and-thread-deep-dive.html)

1 Like
5

Sounds “good”. No VLAN, and this is the last epprom version:

➜  ~ ha os boards raspberrypi firmware
blocked_reason: null
current_version: "2026-05-11"
latest_version: "2026-05-11"
update_available: false
update_blocked: false
update_pending: false

And still have the issue (just test it one more time)

6

Because you’ve changed so much trying to get this to work, not sure where things stand, so let me ask, does your existing Matter/Thread devices still work?

7

I did a lot yeah. But I made a save before any modifications, so I rollback each time I do something.
But yes, all existing connections works well.

8

Usually this is a Thread Credentials problem, but I think you’ve done about everything I would have otherwise suggested. However if you are not seeing any OTBR log entries when commissioning, it is still likely the problem

The other problem that can sometimes be associated with this error is that the phone is not getting the mDNS advertisements which is usually a problem when the phone is on a different LAN/subnet (or even less likely, not using IPv6) than the OTBR, or the home router is somehow blocking these advertisements.

1 Like
9

I already checked mDNS everywhere, and it was all fine… BUT THANK YOU SO MUCH, finally found the issue -_-.

What you said made me think about my whole network setup, and there’s a powerline adapter (CPL) between the router and the Pi 5. I didn’t think it could block anything or mishandle some type of TCP/UDP packets somehow… but I wanted to test it just in case. Plugged directly into the router, and it works!

10

Did you try to generate new conncection data on your phone?