Can't set Thread Border Router as preferred Network

Configuration Matter/Thread
1

My OTBR / Thread network seems to be borked and can’t fix it by deleting it and restarting.

The old preferred network is no longer showing as a Border Router. No idea why that has changed?

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Looks like a new OTBR is showing but I can’t set that as preferred.

The OT integration is also showing as errors. I’ve tried deleting it but it wont allow to to delete it at all. Plan was to delete and restart it.

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The log errors from the OTBR integration are:

Logger: homeassistant.config_entries
Source: /usr/src/homeassistant/homeassistant/config_entries.py:861
First occurred: 18 February 2026 at 22:50:19 (2 occurrences)
Last logged: 18 February 2026 at 22:50:39

Error setting up entry OpenThread Border Router for otbr
Traceback (most recent call last):
  File "/usr/src/homeassistant/homeassistant/config_entries.py", line 762, in __async_setup_with_context
    result = await component.async_setup_entry(hass, self)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/src/homeassistant/homeassistant/components/otbr/__init__.py", line 73, in async_setup_entry
    await update_issues(hass, otbrdata, dataset_tlvs)
  File "/usr/src/homeassistant/homeassistant/components/otbr/util.py", line 268, in update_issues
    _warn_on_default_network_settings(hass, otbrdata, dataset_tlvs)
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/src/homeassistant/homeassistant/components/otbr/util.py", line 224, in _warn_on_default_network_settings
    dataset = tlv_parser.parse_tlv(dataset_tlvs.hex())
  File "/usr/local/lib/python3.13/site-packages/python_otbr_api/tlv_parser.py", line 188, in parse_tlv
    raise TLVError(f"expected {_len} bytes for tag {tag!r}, got {length - pos}")
python_otbr_api.tlv_parser.TLVError: expected 146 bytes for tag 185, got 6

---

Logger: homeassistant.helpers.frame
Source: /usr/src/homeassistant/homeassistant/helpers/frame.py:307
First occurred: 18 February 2026 at 22:50:39 (1 occurrence)
Last logged: 18 February 2026 at 22:50:39

Detected that integration 'otbr' creates a config entry when another entry with the same unique ID exists. This will stop working in Home Assistant 2026.3, please create a bug report at https://github.com/home-assistant/core/issues?q=is%3Aopen+is%3Aissue+label%3A%22integration%3A+otbr%22

I’m using a SLZB-MR1 and have the OTBR app / addon running.

2

“No border routers found” coupled with the OTBR integration error strongly suggests your OTBR app (add-on) is not running — or at least not with the network name and credentials it used to have.

A separate, non-preferred OTBR network is appearing in your list, suggesting either you fired up a third border router, or somehow your add-on’s config changed. Removing and re-adding the OTBR integration to point to this new instance should (should!) give you the option to add it to the old preferred network (via the three-dot menu).

3

I removed / deleted the OTBR and Thread integrations from my HA instance.

I restarted the HA app and the OTBR addon.

I then tried to re-add Thread integration (discovered automatically) and then manually added the OTBR integration once again. But I still get the same errors.

I see no HA preferred Thread network and the other 2nd Thread Network is also showing. Along with the Thread router / network for Tado.

Is there something else I need to do to get this to work or clear out that rouge, additional Thread network?

Would removing the OTBR app completely help?

Logger: homeassistant.config_entries
Source: /usr/src/homeassistant/homeassistant/config_entries.py:861
First occurred: 18:30:55 (1 occurrence)
Last logged: 18:30:55

Error setting up entry Open Thread Border Router for otbr
Traceback (most recent call last):
  File "/usr/src/homeassistant/homeassistant/config_entries.py", line 762, in __async_setup_with_context
    result = await component.async_setup_entry(hass, self)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/src/homeassistant/homeassistant/components/otbr/__init__.py", line 73, in async_setup_entry
    await update_issues(hass, otbrdata, dataset_tlvs)
  File "/usr/src/homeassistant/homeassistant/components/otbr/util.py", line 268, in update_issues
    _warn_on_default_network_settings(hass, otbrdata, dataset_tlvs)
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/src/homeassistant/homeassistant/components/otbr/util.py", line 224, in _warn_on_default_network_settings
    dataset = tlv_parser.parse_tlv(dataset_tlvs.hex())
  File "/usr/local/lib/python3.13/site-packages/python_otbr_api/tlv_parser.py", line 188, in parse_tlv
    raise TLVError(f"expected {_len} bytes for tag {tag!r}, got {length - pos}")
python_otbr_api.tlv_parser.TLVError: expected 146 bytes for tag 185, got 6
4

I was able to fix this issue, by removing the OTBR App and forcing the deletion of the App data.

Then removing both the Thread and OTBR integration.

Once I re-added the OTBR App, and reinstalled the Thread and OTBR integration. Everything started to work as expected again.

I’ve then added the HomeAssistant Thread network into the Tado one (the tado one was in place first). So now there are now two border routers and one Thread network. Best of both worlds.