OTBR app crash-loops on migrate_otbr_settings.py SPINEL timeout with network-connected radio (SLZB-06); full VM restart not always sufficient to recover

[MaranelloAH]

Describe the issue you are experiencing

The OpenThread Border Router app repeatedly fails to start, crash-looping with a TimeoutError in migrate_otbr_settings.py during the SPINEL handshake. This happens with a network-connected Thread radio (SMLIGHT SLZB-06 on the LAN, not a USB dongle), so it doesn't appear to be strictly a USB-passthrough issue like some related reports.

May be related to #4210, #4266, #4475, #4414 — but with a network-connected radio, not USB

What type of installation are you running?

Home Assistant OS

Which operating system are you running on?

Home Assistant Operating System

Which app are you reporting an issue with?

OpenThread Border Router

What is the version of the app?

3.1.0

Steps to reproduce the issue

Not consistently reproducible on demand — occurs intermittently, but once triggered, recurs on every subsequent start attempt.

Steps already taken to rule out the radio itself as the cause

SLZB-06's own web dashboard showed it fully healthy throughout: fresh device uptime after a manual reboot, Ethernet connected via DHCP, reachable via ping.
Socket connected: No on the SLZB-06 the entire time — indicating nothing was even reaching it to attempt a handshake; the migration script times out before a real connection is established.
Restarting just the app: crash-loops immediately, identical traceback every time.
Rebooting the SLZB-06 device: came back clean, app still crash-looped afterward.
Restarting the whole Home Assistant host/VM: resolved the issue the first time it occurred, but on a later occurrence, a full VM restart did not resolve it — suggesting the failure state may persist somewhere beyond the container/network stack

System Health information

System Information

version	core-2026.7.4
installation_type	Home Assistant OS
dev	false
hassio	true
docker	true
container_arch	amd64
user	root
virtualenv	false
python_version	3.14.6
os_name	Linux
os_version	6.18.39-haos
arch	x86_64
timezone	Pacific/Auckland
config_dir	/config

Home Assistant Cloud

logged_in	false
can_reach_cert_server	ok
can_reach_cloud_auth	ok
can_reach_cloud	ok

HACS

GitHub API	ok
GitHub Content	ok
GitHub Web	ok
HACS Data	ok
GitHub API Calls Remaining	5000
Installed Version	2.0.5
Stage	running
Available Repositories	3932
Downloaded Repositories	24

Home Assistant Supervisor

host_os	Home Assistant OS 18.2
update_channel	stable
supervisor_version	supervisor-2026.07.5
agent_version	1.10.0
docker_version	29.6.2
disk_total	46.5 GB
disk_used	27.3 GB
healthy	true
supported	true
host_connectivity	true
supervisor_connectivity	true
ntp_synchronized	true
virtualization	kvm
board	ova
supervisor_api	ok
version_api	ok
installed_addons	Studio Code Server (6.0.1), NGINX Home Assistant SSL proxy (4.5.1), Advanced SSH & Web Terminal (24.0.1), Samba share (12.10.0), Network UPS Tools (0.18.0), Duck DNS (2.0.0), AirSonos (5.1.1), Whisper (3.5.1), Piper (2.3.2), openWakeWord (2.1.1), Music Assistant (2.9.13), MQTT Explorer (browser-1.0.3), Mosquitto broker (7.1.0), Zigbee2MQTT (2.13.0-1), Glances (0.22.0), ESPHome Device Builder (2026.7.4), Matter Server (9.2.0)

Dashboards

dashboards	9
resources	14
views	34
mode	storage

Network Configuration

adapters	lo (disabled), enp0s18 (enabled, default, auto), hassio (disabled), docker0 (disabled), vethe1e96cf (disabled), vethbc47994 (disabled), vethe1c20a1 (disabled), veth86a7968 (disabled), veth66ae453 (disabled), veth15b82d1 (disabled), veth39e163e (disabled), veth95b5254 (disabled), veth52963e8 (disabled), vethc04efea (disabled)

Recorder

oldest_recorder_run	August 13, 2026 at 7:03 AM
current_recorder_run	August 16, 2026 at 7:19 PM
estimated_db_size	419.07 MiB
database_engine	sqlite
database_version	3.53.2

Anything in the Supervisor logs that might be useful for us?

Anything in the app logs that might be useful for us?

[INFO] Migrating OTBR settings if needed...
... Sending frame SpinelFrame(... command_id=<CommandID.RESET: 1> ...)
... Device did not respond to reset, continuing
... Sending frame SpinelFrame(... command_id=<CommandID.PROP_VALUE_GET: 2> ...)
... Failed to send SpinelFrame(...), trying again in 0.10s (attempt 1 of 3)
... Failed to send SpinelFrame(...), trying again in 0.10s (attempt 2 of 3)
... Failed to send SpinelFrame(...), trying again in 0.10s (attempt 3 of 3)
Traceback (most recent call last):
  File ".../universal_silabs_flasher/spinel.py", line 260, in send_frame
    return await asyncio.shield(future)
asyncio.exceptions.CancelledError
...
  File "/usr/local/bin/migrate_otbr_settings.py", line 156, in main
    hwaddr = await get_adapter_hardware_addr(...)
  File "/usr/local/bin/migrate_otbr_settings.py", line 103, in get_adapter_hardware_addr
    rsp = await protocol.send_command(...)
  File ".../universal_silabs_flasher/spinel.py", line 292, in send_command
    return await self.send_frame(frame, **kwargs)
TimeoutError
[WARNING] otbr-agent exited with code 1 (by signal 0).
s6-rc: warning: unable to start service otbr-agent: command exited 1
fatal: stopping the container.

Additional information

Add-on/app version: 3.1.0
Home Assistant OS: 18.2
Home Assistant Core: 2026.7.4
Supervisor: 2026.07.5
Host: Home Assistant OS running as a Proxmox VM
Thread radio: SMLIGHT SLZB-06, connected via LAN using the app's network_device setting (:6638), not USB

Expected behavior

A transient SPINEL communication failure during the settings-migration step shouldn't be treated as fatal for the entire app/container — at minimum, it should retry with backoff or fail gracefully into a state that a normal restart can recover from, rather than requiring destructive workarounds (host reboot) that aren't always effective.

Workaround used

Migrated the affected Matter/Thread devices to Zigbee2MQTT instead, as there was no reliable in-app recovery path.

[Crim]

Hitting the same thing with the same device and symptoms :/

[deb1tux]

Same error for me, but with the Sonoff MG24 Dongle connected via USB

[tloehlein]

Having the exact same issue

[vaind]

Same crash-loop here, with a different radio — SMLIGHT SLZB-MR1 (TI CC2652P7) over LAN (network_device: <slzb-host>:7638), add-on 3.1.1, HA OS 18.2, core 2026.8.3. Identical traceback in migrate_otbr_settings.py → get_adapter_hardware_addr → TimeoutError.

Root cause in my case: the RCP was wedged, and the add-on cannot recover it.

The radio accepted TCP but answered no spinel command. What clears it is a RESET — and the add-on only ever sends one:

Sending frame CommandID.RESET  →  Sent 7 of 7 bytes
Device did not respond to reset, continuing      <-- gives up on RESET here
Sending frame CommandID.PROP_VALUE_GET (HWADDR)
Failed to send ... (attempt 1 of 3 / 2 of 3 / 3 of 3)  →  TimeoutError

The three retries re-send only the HWADDR query, never the reset. So the wedge persists: an add-on restart, a full host reboot, and rebooting the radio itself all failed with the identical traceback.

One difference from the title worth noting: mine didn't crash-loop. It failed once, then sat in error and never retried on its own.

Recovery: I connected to :7638 directly, held the socket open, and sent the add-on's own frame 7e800102eaf07e (verified byte-identical). The radio replied instantly and stayed responsive:

RESET            -> 7e80060070ee747e   LAST_STATUS 0x70 = RESET_SOFTWARE
NCP_VERSION      -> OPENTHREAD/1.4.0.0; CC13XX_CC26XX thread-v1.4-ti-1.0-ea-1.0; SLZB-06P7 20260304
HWADDR           -> 00:12:4b:xx:xx:xx:xx:xx   (00:12:4B = Texas Instruments OUI)

The next add-on restart succeeded on the first try → Role child -> router, Backbone Router becomes Primary!. Firmware, radio mode (Thread RCP, PROD), and baud (460800, HW flow off) were correct throughout and never changed.

One note that may help narrow this:

The adapter query gates startup even when the migration turns out to be a no-op. Once the radio answered, the script logged Adapter settings file /data/thread/0_<hwaddr>.data is the most recently used, skipping — there was nothing to do. But it can only reach that conclusion after get_adapter_hardware_addr() succeeds, so an unresponsive radio blocks container startup on a query whose only purpose was to establish that no migration was needed. Note this is not covered by #4482: its early return fires only when there are no .data files at all, and here there is one.

Two changes that would have helped in this case: retrying RESET rather than giving up after a single unanswered attempt and retrying only the property read; and treating a failed adapter query as non-fatal instead of exiting 1 and taking the container down with it.

[TungstenE2]

same issue here. Any update?

---

Add-on: OpenThread Border Router
OpenThread Border Router app

Add-on version: 3.1.2
You are running the latest version of this add-on.
System: Home Assistant OS 18.2 (amd64 / generic-x86-64)
Home Assistant Core: 2026.8.3
Home Assistant Supervisor: 2026.08.0

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 otbr-agent: starting
[09:18:52] INFO: Migrating OTBR settings if needed...
2026-08-29 09:18:52 homeassistant asyncio[235] DEBUG Using selector: EpollSelector
2026-08-29 09:18:52 homeassistant zigpy.serial[235] DEBUG Opening a serial connection to '/dev/serial/by-id/usb-SONOFF_SONOFF_Dongle_Plus_MG24_1e5e1c61b69aef11bd5fb29061ce3355-if00-port0' (baudrate=460800, xonxoff=False, rtscts=False)
2026-08-29 09:18:52 homeassistant serialx.platforms.serial_posix[235] DEBUG Locking serial port '/dev/serial/by-id/usb-SONOFF_SONOFF_Dongle_Plus_MG24_1e5e1c61b69aef11bd5fb29061ce3355-if00-port0'
2026-08-29 09:18:52 homeassistant serialx.platforms.serial_posix[235] DEBUG Configuring serial port '/dev/serial/by-id/usb-SONOFF_SONOFF_Dongle_Plus_MG24_1e5e1c61b69aef11bd5fb29061ce3355-if00-port0'
2026-08-29 09:18:52 homeassistant serialx.platforms.serial_posix[235] DEBUG Configuring serial port: TcsetattrFlags(iflag=0, oflag=0, cflag=3248, lflag=0, ispeed=4100, ospeed=4100, cc_vmin=0, cc_vtime=0) + cc=[b'\x03', b'\x1c', b'\x7f', b'\x15', b'\x04', 0, 0, b'\x00', b'\x11', b'\x13', b'\x1a', b'\x00', b'\x12', b'\x0f', b'\x17', b'\x16', b'\x00', b'\x00', b'\x00', b'\x00', b'\x00', b'\x00', b'\x00', b'\x00', b'\x00', b'\x00', b'\x00', b'\x00', b'\x00', b'\x00', b'\x00', b'\x00']
2026-08-29 09:18:52 homeassistant serialx.platforms.serial_linux[235] DEBUG Setting low latency mode: True
2026-08-29 09:18:52 homeassistant serialx.platforms.serial_posix[235] DEBUG Setting modem pins: ModemPins[!dtr !rts]
2026-08-29 09:18:52 homeassistant serialx.platforms.serial_posix[235] DEBUG TIOCMBIC: 0x00000006
2026-08-29 09:18:52 homeassistant zigpy.serial[235] DEBUG Connection made: <serialx.platforms.serial_linux.LinuxSerialTransport object at 0x7f80cbc081d0>
2026-08-29 09:18:52 homeassistant universal_silabs_flasher.spinel[235] DEBUG Sending frame SpinelFrame(header=SpinelHeader(transaction_id=0, network_link_id=0, flag=2), command_id=<CommandID.RESET: 1>, data=b'\x02')
2026-08-29 09:18:52 homeassistant universal_silabs_flasher.spinel[235] DEBUG Sending data b'\x80\x01\x02\xea\xf0'
2026-08-29 09:18:52 homeassistant serialx.descriptor_transport[235] DEBUG Immediately writing b'\x80\x01\x02\xea\xf0'
2026-08-29 09:18:52 homeassistant serialx.descriptor_transport[235] DEBUG Sent 7 of 7 bytes
2026-08-29 09:18:54 homeassistant universal_silabs_flasher.spinel[235] DEBUG Device did not respond to reset, continuing
2026-08-29 09:18:54 homeassistant universal_silabs_flasher.spinel[235] 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')
2026-08-29 09:18:54 homeassistant universal_silabs_flasher.spinel[235] DEBUG Sending data b'\x83\x02\x08\xbc\x9a'
2026-08-29 09:18:54 homeassistant serialx.descriptor_transport[235] DEBUG Immediately writing b'\x83\x02\x08\xbc\x9a'
2026-08-29 09:18:54 homeassistant serialx.descriptor_transport[235] DEBUG Sent 7 of 7 bytes
2026-08-29 09:18:56 homeassistant universal_silabs_flasher.spinel[235] DEBUG Failed to send SpinelFrame(header=SpinelHeader(network_link_id=0, flag=2), command_id=<CommandID.PROP_VALUE_GET: 2>, data=b'\x08'), trying again in 0.10s (attempt 1 of 3)
2026-08-29 09:18:56 homeassistant universal_silabs_flasher.spinel[235] 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')
2026-08-29 09:18:56 homeassistant universal_silabs_flasher.spinel[235] DEBUG Sending data b'\x83\x02\x08\xbc\x9a'
2026-08-29 09:18:56 homeassistant serialx.descriptor_transport[235] DEBUG Immediately writing b'\x83\x02\x08\xbc\x9a'
2026-08-29 09:18:56 homeassistant serialx.descriptor_transport[235] DEBUG Sent 7 of 7 bytes
2026-08-29 09:18:58 homeassistant universal_silabs_flasher.spinel[235] DEBUG Failed to send SpinelFrame(header=SpinelHeader(network_link_id=0, flag=2), command_id=<CommandID.PROP_VALUE_GET: 2>, data=b'\x08'), trying again in 0.10s (attempt 2 of 3)
2026-08-29 09:18:58 homeassistant universal_silabs_flasher.spinel[235] 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')
2026-08-29 09:18:58 homeassistant universal_silabs_flasher.spinel[235] DEBUG Sending data b'\x83\x02\x08\xbc\x9a'
2026-08-29 09:18:58 homeassistant serialx.descriptor_transport[235] DEBUG Immediately writing b'\x83\x02\x08\xbc\x9a'
2026-08-29 09:18:58 homeassistant serialx.descriptor_transport[235] DEBUG Sent 7 of 7 bytes
2026-08-29 09:19:00 homeassistant universal_silabs_flasher.spinel[235] DEBUG Failed to send SpinelFrame(header=SpinelHeader(network_link_id=0, flag=2), command_id=<CommandID.PROP_VALUE_GET: 2>, data=b'\x08'), trying again in 0.10s (attempt 3 of 3)
2026-08-29 09:19:00 homeassistant serialx.descriptor_transport[235] DEBUG Closing at the request of the application
2026-08-29 09:19:00 homeassistant serialx.descriptor_transport[235] DEBUG Backgrounding a close request: None
2026-08-29 09:19:00 homeassistant zigpy.serial[235] DEBUG Waiting for serial port to close
2026-08-29 09:19:00 homeassistant serialx.descriptor_transport[235] DEBUG Closing connection: None
2026-08-29 09:19:00 homeassistant serialx.descriptor_transport[235] DEBUG Closing file descriptor 7
2026-08-29 09:19:00 homeassistant serialx.descriptor_transport[235] DEBUG Calling protocol connection_lost with exc=None
2026-08-29 09:19:00 homeassistant zigpy.serial[235] DEBUG Connection lost: None
Traceback (most recent call last):
File "/usr/local/lib/python3.13/dist-packages/universal_silabs_flasher/spinel.py", line 260, in send_frame
return await asyncio.shield(future)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^
asyncio.exceptions.CancelledError
The above exception was the direct cause of the following exception:
Traceback (most recent call last):
File "/usr/local/bin/migrate_otbr_settings.py", line 228, in
asyncio.run(main())
~~~~~~~~~~~^^^^^^^^
File "/usr/lib/python3.13/asyncio/runners.py", line 195, in run
return runner.run(main)
~~~~~~~~~~^^^^^^
File "/usr/lib/python3.13/asyncio/runners.py", line 118, in run
return self._loop.run_until_complete(task)
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^
File "/usr/lib/python3.13/asyncio/base_events.py", line 725, in run_until_complete
return future.result()
~~~~~~~~~~~~~^^
File "/usr/local/bin/migrate_otbr_settings.py", line 156, in main
hwaddr = await get_adapter_hardware_addr(
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
...<3 lines>...
)
^
File "/usr/local/bin/migrate_otbr_settings.py", line 103, in get_adapter_hardware_addr
rsp = await protocol.send_command(
^^^^^^^^^^^^^^^^^^^^^^^^^^^^
...<2 lines>...
)
^
File "/usr/local/lib/python3.13/dist-packages/universal_silabs_flasher/spinel.py", line 292, in send_command
return await self.send_frame(frame, **kwargs)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.13/dist-packages/universal_silabs_flasher/spinel.py", line 259, in send_frame
async with asyncio_timeout(timeout):
~~~~~~~~~~~~~~~^^^^^^^^^
File "/usr/lib/python3.13/asyncio/timeouts.py", line 116, in aexit
raise TimeoutError from exc_val
TimeoutError
[09:19:01] WARNING: otbr-agent exited with code 1 (by signal 0).
Chain OTBR_FORWARD_INGRESS (0 references)
target prot opt source destination
ACCEPT all -- anywhere anywhere
otbr-ingress-deny-src
otbr-ingress-deny-src-swap
otbr-ingress-allow-dst
otbr-ingress-allow-dst-swap
Chain OTBR_FORWARD_EGRESS (0 references)
target prot opt source destination
ACCEPT all -- anywhere anywhere
Chain OTBR_FORWARD_NAT64 (0 references)
target prot opt source destination
ACCEPT all -- 0.0.0.0/0 0.0.0.0/0 mark match 0x1001
ACCEPT all -- 0.0.0.0/0 0.0.0.0/0 ctstate RELATED,ESTABLISHED
[09:19:01] INFO: OTBR firewall/NAT64 rules teardown completed.
s6-svlisten: fatal: some services reported permanent failure or their supervisor died
s6-rc: warning: unable to start service otbr-agent: command exited 1
/run/s6/basedir/scripts/rc.init: warning: s6-rc failed to properly bring all the services up! Check your logs (in /run/uncaught-logs/current if you have in-container logging) for more information.
/run/s6/basedir/scripts/rc.init: fatal: stopping the container.
s6-rc: info: service legacy-cont-init: stopping
s6-rc: info: service banner: stopping
s6-rc: info: service banner successfully stopped
s6-rc: info: service legacy-cont-init successfully stopped
s6-rc: info: service fix-attrs: stopping
s6-rc: info: service fix-attrs successfully stopped
s6-rc: warning: service s6rc-oneshot-runner is marked as essential, not stopping it