OTBR not working with SLZB-MR4u

[aguspa]

Hello,

It seems that the new SLZB-MR4u is not working with the OTBR addon in HA via LAN.
If I use my old SLZB-06 everything works, but if I change the IP to my new SLZB-MR4u I get errors.

SMLight support says: “Most likely, the OTBR addon is currently broken, unfortunately this cannot be fixed on our side. Please post a bug report in the addon developer repository”

Log:

[12:26:16] INFO: Starting mDNS Responder...
Default: mDNSResponder (Engineering Build) (Oct 28 2025 07:36:47) starting
s6-rc: info: service legacy-cont-init successfully started
[12:26:16] INFO: Starting socat TCP client for OTBR daemon...
-----------------------------------------------------------
 Add-on: OpenThread Border Router
 OpenThread Border Router add-on
-----------------------------------------------------------
 Add-on version: 2.15.0
 You are running the latest version of this add-on.
 System: Home Assistant OS 16.2  (amd64 / qemux86-64)
 Home Assistant Core: 2025.10.4
 Home Assistant Supervisor: 2025.10.0
-----------------------------------------------------------
 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 socat-otbr-tcp successfully started
s6-rc: info: service otbr-agent: starting
[12:26:17] INFO: Setup OTBR firewall...
[12:26:17] INFO: Migrating OTBR settings if needed...
2025-11-03 12:26:17 homeassistant asyncio[246] DEBUG Using selector: EpollSelector
2025-11-03 12:26:17 homeassistant zigpy.serial[246] DEBUG Opening a serial connection to '/tmp/ttyOTBR' (baudrate=460800, xonxoff=False, rtscts=False)
2025-11-03 12:26:17 homeassistant zigpy.serial[246] DEBUG Connection made: SerialTransport(<_UnixSelectorEventLoop running=True closed=False debug=False>, <universal_silabs_flasher.spinel.SpinelProtocol object at 0x7f861e3700d0>, Serial<id=0x7f861e364a30, open=True>(port='/tmp/ttyOTBR', baudrate=460800, bytesize=8, parity='N', stopbits=1, timeout=0, xonxoff=False, rtscts=False, dsrdtr=False))
2025-11-03 12:26:17 homeassistant universal_silabs_flasher.spinel[246] DEBUG Sending frame SpinelFrame(header=SpinelHeader(transaction_id=3, network_link_id=0, flag=2), command_id=<CommandID.PROP_VALUE_GET: 2>, data=b'\x08')
2025-11-03 12:26:17 homeassistant universal_silabs_flasher.spinel[246] DEBUG Sending data b'~\x83\x02\x08\xbc\x9a~'
2025-11-03 12:26:18 homeassistant universal_silabs_flasher.spinel[246] DEBUG Decoded HDLC frame: HDLCLiteFrame(data=b'\x83\x06\x08D\x9f\xda\xff\xfex\xa7\xba')
2025-11-03 12:26:18 homeassistant universal_silabs_flasher.spinel[246] DEBUG Parsed frame SpinelFrame(header=SpinelHeader(transaction_id=3, network_link_id=0, flag=2), command_id=<CommandID.PROP_VALUE_IS: 6>, data=b'\x08D\x9f\xda\xff\xfex\xa7\xba')
2025-11-03 12:26:18 homeassistant zigpy.serial[246] DEBUG Waiting for serial port to close
2025-11-03 12:26:18 homeassistant zigpy.serial[246] DEBUG Connection lost: None
Settings file for adapter 449fdafffe78a7ba already exists at /data/thread/0_449fdafffe78a7ba.data but appears to be old, archiving
Wrote new settings file to /data/thread/0_449fdafffe78a7ba.data
[12:26:18] INFO: Starting otbr-agent...
[NOTE]-AGENT---: Running 0.3.0-b067e5ac-dirty
[NOTE]-AGENT---: Thread version: 1.3.0
tiocmbic: Inappropriate ioctl for device
[NOTE]-AGENT---: Thread interface: wpan0
[NOTE]-AGENT---: Radio URL: spinel+hdlc+uart:///tmp/ttyOTBR?uart-baudrate=460800&uart-init-deassert
[NOTE]-AGENT---: Radio URL: trel://enp0s3
[NOTE]-ILS-----: Infra link selected: enp0s3
[INFO]-RCP_HOS-: OpenThread log level changed to 5
53d.17:37:14.576 [D] P-SpinelDrive-: Sent spinel frame, flg:0x2, iid:0, tid:0, cmd:RESET
53d.17:37:14.576 [D] P-SpinelDrive-: Waiting response: key=0
53d.17:37:14.584 [D] P-SpinelDrive-: Received spinel frame, flg:0x2, iid:0, tid:0, cmd:PROP_VALUE_IS, key:LAST_STATUS, status:RESET_POWER_ON
53d.17:37:14.584 [I] P-SpinelDrive-: co-processor reset: RESET_POWER_ON
53d.17:37:14.584 [C] P-SpinelDrive-: Software reset co-processor successfully
53d.17:37:14.584 [D] P-SpinelDrive-: Sent spinel frame, flg:0x2, iid:0, tid:1, cmd:PROP_VALUE_GET, key:PROTOCOL_VERSION
53d.17:37:14.584 [D] P-SpinelDrive-: Waiting response: key=1
53d.17:37:14.595 [D] P-SpinelDrive-: Received spinel frame, flg:0x2, iid:0, tid:1, cmd:PROP_VALUE_IS, key:PROTOCOL_VERSION, major:4, minor:3
53d.17:37:14.595 [D] P-SpinelDrive-: Sent spinel frame, flg:0x2, iid:0, tid:1, cmd:PROP_VALUE_GET, key:NCP_VERSION
53d.17:37:14.595 [D] P-SpinelDrive-: Waiting response: key=2
53d.17:37:14.607 [D] P-SpinelDrive-: Received spinel frame, flg:0x2, iid:0, tid:1, cmd:PROP_VALUE_IS, key:NCP_VERSION, version:SL-OPENTHREAD/2.7.0.0_GitHub-fb0446f53; EFR32; Jul  3 2025 01:25:59
53d.17:37:14.608 [D] P-SpinelDrive-: Sent spinel frame, flg:0x2, iid:0, tid:1, cmd:PROP_VALUE_GET, key:CAPS
53d.17:37:14.608 [D] P-SpinelDrive-: Waiting response: key=5
53d.17:37:14.618 [D] P-SpinelDrive-: Received spinel frame, flg:0x2, iid:0, tid:1, cmd:PROP_VALUE_IS, key:CAPS, caps:COUNTERS UNSOL_UPDATE_FILTER 802_15_4_2450MHZ_OQPSK CONFIG_RADIO MAC_RAW RCP_API_VERSION RCP_MIN_HOST_API_VERSION RCP_RESET_TO_BOOTLOADER RCP_LOG_CRASH_DUMP OPENTHREAD_LOG_METADATA 
[INFO]-BA------: Ephemeral Key is: disabled during initialization
53d.17:37:14.619 [D] P-SpinelDrive-: Sent spinel frame, flg:0x2, iid:0, tid:1, cmd:PROP_VALUE_GET, key:HWADDR
53d.17:37:14.619 [D] P-RadioSpinel-: Wait response: tid=1 key=8
53d.17:37:14.629 [D] P-SpinelDrive-: Received spinel frame, flg:0x2, iid:0, tid:1, cmd:PROP_VALUE_IS, key:HWADDR, eui64:449fdafffe78a7ba
53d.17:37:14.629 [D] P-RadioSpinel-: RCP supports crash dump logging. Requesting crash dump.
53d.17:37:14.629 [D] P-SpinelDrive-: Sent spinel frame, flg:0x2, iid:0, tid:2, cmd:PROP_VALUE_SET, key:RCP_LOG_CRASH_DUMP, log-crash-dump
53d.17:37:14.629 [D] P-RadioSpinel-: Wait response: tid=2 key=178
53d.17:37:14.640 [W] P-HdlcIntface-: Error decoding hdlc frame: Parse
53d.17:37:16.631 [W] P-RadioSpinel-: Wait for response timeout
53d.17:37:16.631 [W] P-RadioSpinel-: RCP failure detected
53d.17:37:16.631 [W] P-RadioSpinel-: Trying to recover (1/2)
53d.17:37:16.631 [D] P-SpinelDrive-: Sent spinel frame, flg:0x2, iid:0, tid:1, cmd:PROP_VALUE_SET, key:PHY_ENABLED, enabled:1
53d.17:37:16.631 [D] P-RadioSpinel-: Wait response: tid=1 key=32
53d.17:37:16.639 [D] P-SpinelDrive-: Received spinel frame, flg:0x2, iid:0, tid:1, cmd:PROP_VALUE_IS, key:PHY_ENABLED, enabled:1
53d.17:37:16.639 [D] P-SpinelDrive-: Sent spinel frame, flg:0x2, iid:0, tid:2, cmd:PROP_VALUE_SET, key:MAC_15_4_PANID, panid:0xffff
53d.17:37:16.639 [D] P-RadioSpinel-: Wait response: tid=2 key=54
53d.17:37:16.650 [D] P-SpinelDrive-: Received spinel frame, flg:0x2, iid:0, tid:2, cmd:PROP_VALUE_IS, key:MAC_15_4_PANID, panid:0xffff
53d.17:37:16.650 [D] P-SpinelDrive-: Sent spinel frame, flg:0x2, iid:0, tid:3, cmd:PROP_VALUE_SET, key:MAC_15_4_SADDR, saddr:0x0000
53d.17:37:16.650 [D] P-RadioSpinel-: Wait response: tid=3 key=53
53d.17:37:16.661 [D] P-SpinelDrive-: Received spinel frame, flg:0x2, iid:0, tid:3, cmd:PROP_VALUE_IS, key:MAC_15_4_SADDR, saddr:0x0000
53d.17:37:16.661 [D] P-SpinelDrive-: Sent spinel frame, flg:0x2, iid:0, tid:4, cmd:PROP_VALUE_SET, key:MAC_15_4_LADDR, laddr:0000000000000000
53d.17:37:16.661 [D] P-RadioSpinel-: Wait response: tid=4 key=52
53d.17:37:16.672 [D] P-SpinelDrive-: Received spinel frame, flg:0x2, iid:0, tid:4, cmd:PROP_VALUE_IS, key:MAC_15_4_LADDR, laddr:0000000000000000
53d.17:37:16.672 [D] P-SpinelDrive-: Sent spinel frame, flg:0x2, iid:0, tid:5, cmd:PROP_VALUE_SET, key:PHY_CHAN, channel:0
53d.17:37:16.672 [D] P-RadioSpinel-: Wait response: tid=5 key=33
53d.17:37:16.683 [D] P-SpinelDrive-: Received spinel frame, flg:0x2, iid:0, tid:5, cmd:PROP_VALUE_IS, key:PHY_CHAN, channel:0
53d.17:37:16.683 [D] P-RadioSpinel-: RCP supports crash dump logging. Requesting crash dump.
53d.17:37:16.683 [D] P-SpinelDrive-: Sent spinel frame, flg:0x2, iid:0, tid:6, cmd:PROP_VALUE_SET, key:RCP_LOG_CRASH_DUMP, log-crash-dump
53d.17:37:16.683 [D] P-RadioSpinel-: Wait response: tid=6 key=178
53d.17:37:16.694 [W] P-HdlcIntface-: Error decoding hdlc frame: Parse
53d.17:37:18.685 [W] P-RadioSpinel-: Wait for response timeout
53d.17:37:18.685 [W] P-RadioSpinel-: RCP failure detected
53d.17:37:18.685 [W] P-RadioSpinel-: Trying to recover (1/2)
53d.17:37:18.685 [D] P-SpinelDrive-: Sent spinel frame, flg:0x2, iid:0, tid:1, cmd:PROP_VALUE_SET, key:PHY_ENABLED, enabled:1
53d.17:37:18.685 [D] P-RadioSpinel-: Wait response: tid=1 key=32
53d.17:37:18.692 [D] P-SpinelDrive-: Received spinel frame, flg:0x2, iid:0, tid:1, cmd:PROP_VALUE_IS, key:PHY_ENABLED, enabled:1
53d.17:37:18.692 [D] P-SpinelDrive-: Sent spinel frame, flg:0x2, iid:0, tid:2, cmd:PROP_VALUE_SET, key:MAC_15_4_PANID, panid:0xffff
53d.17:37:18.692 [D] P-RadioSpinel-: Wait response: tid=2 key=54
53d.17:37:18.703 [D] P-SpinelDrive-: Received spinel frame, flg:0x2, iid:0, tid:2, cmd:PROP_VALUE_IS, key:MAC_15_4_PANID, panid:0xffff
53d.17:37:18.703 [D] P-SpinelDrive-: Sent spinel frame, flg:0x2, iid:0, tid:3, cmd:PROP_VALUE_SET, key:MAC_15_4_SADDR, saddr:0x0000
53d.17:37:18.703 [D] P-RadioSpinel-: Wait response: tid=3 key=53
53d.17:37:18.714 [D] P-SpinelDrive-: Received spinel frame, flg:0x2, iid:0, tid:3, cmd:PROP_VALUE_IS, key:MAC_15_4_SADDR, saddr:0x0000
53d.17:37:18.714 [D] P-SpinelDrive-: Sent spinel frame, flg:0x2, iid:0, tid:4, cmd:PROP_VALUE_SET, key:MAC_15_4_LADDR, laddr:0000000000000000
53d.17:37:18.714 [D] P-RadioSpinel-: Wait response: tid=4 key=52
53d.17:37:18.725 [D] P-SpinelDrive-: Received spinel frame, flg:0x2, iid:0, tid:4, cmd:PROP_VALUE_IS, key:MAC_15_4_LADDR, laddr:0000000000000000
53d.17:37:18.725 [D] P-SpinelDrive-: Sent spinel frame, flg:0x2, iid:0, tid:5, cmd:PROP_VALUE_SET, key:PHY_CHAN, channel:0
53d.17:37:18.725 [D] P-RadioSpinel-: Wait response: tid=5 key=33
53d.17:37:18.736 [D] P-SpinelDrive-: Received spinel frame, flg:0x2, iid:0, tid:5, cmd:PROP_VALUE_IS, key:PHY_CHAN, channel:0
53d.17:37:18.736 [D] P-RadioSpinel-: RCP supports crash dump logging. Requesting crash dump.
53d.17:37:18.736 [D] P-SpinelDrive-: Sent spinel frame, flg:0x2, iid:0, tid:6, cmd:PROP_VALUE_SET, key:RCP_LOG_CRASH_DUMP, log-crash-dump
53d.17:37:18.736 [D] P-RadioSpinel-: Wait response: tid=6 key=178
53d.17:37:18.747 [W] P-HdlcIntface-: Error decoding hdlc frame: Parse
53d.17:37:20.738 [W] P-RadioSpinel-: Wait for response timeout
53d.17:37:20.738 [W] P-RadioSpinel-: RCP failure detected
53d.17:37:20.738 [W] P-RadioSpinel-: Trying to recover (1/2)
53d.17:37:20.738 [D] P-SpinelDrive-: Sent spinel frame, flg:0x2, iid:0, tid:1, cmd:PROP_VALUE_SET, key:PHY_ENABLED, enabled:1
53d.17:37:20.738 [D] P-RadioSpinel-: Wait response: tid=1 key=32

My config:

device: /dev/ttyS1
baudrate: "460800"
flow_control: false
otbr_log_level: debug
firewall: true
nat64: false
network_device: 192.168.1.163:6638

Same problem here: https://www.reddit.com/r/homeassistant/comments/1oj88mt/smlight_mr4u/

Thanks!

[emosan (Raul)]

I had the same issue, Reflash the EFR32MG26 chip in the SLZB-MR4 and everything will work again.

[TheDoc97 (Han Arts)]

Hi, with the new firmware 3.10 all is working

[ha_user33]

Were you able to get this working? I also have the SMLIGHT SLZB-MR4U and I am having these issues:

Errors trying to setup Matter-over-Thread with the SMLIGHT SLZB-MR4U

I think I set everything correctly. I followed this guide on the SMLight website: SMLight SLZB-MR4U I am using the Radio 1 (EFR32MG26) as Matter-over-Thread. [EFR32MG26 as Matter-over-Thread] OpenThread Border Router I get these errors in the logs: 06:26:42.881 [W] P-RadioSpinel-: radio tx timeout 06:26:42.881 [W] P-RadioSpinel-: RCP failure detected 06:26:42.881 [W] P-RadioSpinel-: Trying to recover (1/2) 06:26:43.030 [C] P-RadioSpinel-: RCP => [C] Platform------: Reset info: 0x3 (EXT) 06…

[umrath (Thoralf Will)]

I have unsuccessfully tried to get the SLZB MR4U to work with HomeAssistant/OpenThread Border Router so far.

I am able to connect the device - but the whatever the dongle does - the connection is not stable.

In parallel I tried a Google Nest Hub 2 as Border Router - and it works rock solid.

Whenever I connect the SLZB the connections start to drop and get erratic. Same, when I run it standalone (without the Nest Hub).
Whenever I return to run the Nest Hub alone, everything is fine again.

I have an open ticket with SMLight. But so far I have not received any feedback that solves the issue.

[sparkydave (🇦🇺 Dave)]

Which radio are you using for Zigbee vs Thread? Their website has a recommended config.

[umrath (Thoralf Will)]

I am indeed using the MG26.
But I also tried the P10 - with the very same results.

I also tried to connect the dongle via USB, to rule out any network related issues - which did not change anything.

So, I’m fairly certain that the issue is somewhere between the dongle itself (including the firmware) and the Open Thread Border router addon in Homeassistant.

[starob]

For me this setup works. MR4U is connected via LAN. I use HA 2026.1.x
I have 40+ Zigbee devices but only a few IKEA matter devices.

With this MoT Firmware:

OTBR Version 2.15.3

OTBR Config

baudrate: "460800"
flow_control: false
otbr_log_level: notice
firewall: false
nat64: false
network_device: 192.168.1.79:6638

The Thread integration shows this:

Last Important Step → Synchronize Thread Credentials:

In HA Android App: Setup → Companion App → Troubleshooting → Sync Thread Credentials

For me this now works with IKEA Matter devices and is stable. In parallel I run Zigbee on the same MR4U without any issues.

Hope this helps.

[umrath (Thoralf Will)]

About 10 days ago I got an updated firmware from SMLight (which is now the dev version 20251218) - and that one works for me.

I had a single incident 3 days ago where I lost my 2 bilresa buttons and had to newly pair them. But I hope that this was just a temporary glitch.