core ZBT-2 installation fails with "not_implemented" error message

The problem

I plugged in a new ZBT-2. Installing the integration fails.

The first attempt at installing the ZBT-2 integration fails with an exception: RuntimeError: Failed to probe running application type

All subsequent attempts at installing the integration fail. Each time, a popup error message on the Integrations page says:

Home Assistant Connect ZBT-2 not_implemented

No other messages are logged.

What version of Home Assistant Core has the issue?

core-2025.12.3

What was the last working version of Home Assistant Core?

No response

What type of installation are you running?

Home Assistant OS

Integration causing the issue

ZBT-2

Link to integration documentation on our website

https://www.home-assistant.io/integrations/homeassistant_connect_zbt2

Diagnostics information

I do not find any downloadable diagnostic data for this integration.

Instead, these messages are logged:

Logger: homeassistant.components.homeassistant_hardware.firmware_config_flow Source: components/homeassistant_hardware/firmware_config_flow.py:203 integration: Home Assistant Hardware (documentation, issues) First occurred: 1:48:20 PM (1 occurrence) Last logged: 1:48:20 PM

Failed to flash firmware Traceback (most recent call last): File "/usr/src/homeassistant/homeassistant/components/homeassistant_hardware/util.py", line 421, in async_flash_silabs_firmware await flasher.enter_bootloader() File "/usr/local/lib/python3.13/site-packages/universal_silabs_flasher/flasher.py", line 358, in enter_bootloader await self.probe_app_type() File "/usr/local/lib/python3.13/site-packages/universal_silabs_flasher/flasher.py", line 329, in probe_app_type raise RuntimeError("Failed to probe running application type") RuntimeError: Failed to probe running application type

The above exception was the direct cause of the following exception:

Traceback (most recent call last): File "/usr/src/homeassistant/homeassistant/components/homeassistant_hardware/firmware_config_flow.py", line 203, in _install_firmware_step await self.firmware_install_task File "/usr/src/homeassistant/homeassistant/components/homeassistant_hardware/firmware_config_flow.py", line 310, in _install_firmware self._probed_firmware_info = await async_flash_silabs_firmware( ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ ...<9 lines>... ) ^ File "/usr/src/homeassistant/homeassistant/components/homeassistant_hardware/util.py", line 430, in async_flash_silabs_firmware raise HomeAssistantError("Failed to flash firmware") from err homeassistant.exceptions.HomeAssistantError: Failed to flash firmware

Example YAML snippet

Anything in the logs that might be useful for us?

Additional information

This isn't a new installation. Home Assistant has been running reliably on this hardware for 2 years. The only recent change is the installation of the ZBT-2.

Dec 18 '25 23:12 jeffstearns

Hey there @home-assistant/core, mind taking a look at this issue as it has been labeled with an integration (homeassistant_hardware) you are listed as a code owner for? Thanks!

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Dec 18 '25 23:12 home-assistant[bot]

Hey there @home-assistant/core, mind taking a look at this issue as it has been labeled with an integration (homeassistant_connect_zbt2) you are listed as a code owner for? Thanks!

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Dec 18 '25 23:12 home-assistant[bot]

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Dec 18 '25 23:12 coderabbitai[bot]

For what it's worth: I had the same issue and the fix was to plug the antenna cable into a different USB port. I moved it from a USB 3 port to a USB 2 port and restarted everything. After that detection and firmware flashing was no problem.

Dec 21 '25 10:12 dataflake

Using a USB 2 port didn't help for me.

But I just managed to overcome this problem by powering down the host computer (and the connected ZBT-2 adapter) overnight. After powering it on the next morning, I was able to flash firmware.

I don't know whether it was the HA reboot or the long-term power outage that overcame the problem.

Flashing firmware onto the ZBT-2 definitely seems problematic. Maybe the documentation needs to be updated with some suggested workarounds until the code becomes more reliable.

Dec 22 '25 22:12 jeffstearns