SLZB-06M and OTBR - Can't add device

Configuration Matter/Thread
1

I’m trying to set up OTBR on my HA instance (running on a VM in Synology), with a SLZB-06M connected via Ethernet (PoE).
OTBR seems to be starting correctly (I have one border router showing in the Threads integration), and HA seems to be set up with IPv6
When I try adding a device (Aquara FP300) I always end up with “Your device requires a Thread border router”

I see the following log in OTBR repeated many times during/after the connection attempt

00:01:21.299 [W] P-HdlcIntface-: Error decoding hdlc frame: Parse

-----------------------------------------------------------
 Add-on: OpenThread Border Router
 OpenThread Border Router add-on
-----------------------------------------------------------
 Add-on version: 2.15.1
 You are running the latest version of this add-on.
s6-rc: info: service socat-otbr-tcp successfully started
 System: Home Assistant OS 16.3  (amd64 / qemux86-64)
 Home Assistant Core: 2025.11.2
 Home Assistant Supervisor: 2025.11.4

Model: 	SLZB-06M
	Radio 	Core
CPU model: 	EFR32MG21 	ESP32
CPU cores and clock: 	1 @ 80MHz 	2 @ 240 Mhz
Flash memory: 	768 kB 	16Mb
RAM memory: 	96 Kb 	119/295KiB
Largest free block: 	- 	107KiB
SoC temperature: 	38.28°C 	39.44°C
Firmware version: 	20241105 	v3.1.3
Latest FW check: 	22/11/2025 	22/11/2025
2

Nevermind, managed to get it working. I was missing a few steps from Connecting Matter-over-Thread Device to Home Assistant | SLZB-06 * Series Manual

3

which steps were they because I can’t for the life of me figure out what I’m doing wrong. I’ve been reading and re-reading those instructions for a while now.

edit
So I had to also show the ports not currently in use and type them in, in the border-router add-in (not device). Once I did that, HA automatically added the device. The greyed out ports don’t do anything, you have to type those into the box. It was not in the instructions.