This section has two goals:

1. List the currently available firmware options for Home Assistant Yellow and Connect ZBT-1.
2. List the different add-ons and integrations related to these options and show their relationships.

Currently available firmware

There are currently 2 different recommended firmware options available for Home Assistant Yellow:

1. Zigbee firmware
   • This is the firmware that runs a Zigbee network. It is preinstalled on Connect ZBT-1 and Yellow.
   • Bundled in the Silicon Labs Flasher add-on. In case you have installed one of the other two options at some point, this add-on allows you to re-install the Zigbee firmware. Note that the add-on is only used to flash the firmware. It is never used during operation: ZHA communicates with the Zigbee firmware directly.
   • Other terms you may have seen to designate this firmware: EmberZNet firmware, EZSP firmware, Zigbee EZSP.
2. Thread firmware
   • This firmware allows to use Yellow or Connect ZBT-1 as a dedicated Thread border router when used with the Open Thread Border Router addon.
   • Bundled in the Open Thread Border Router add-on.
   • Other terms you may have seen to designate this firmware: OpenThread RCP, RCP OT

There is also an experimental firmware, which is not recommended: the Multiprotocol firmware

• This is the firmware that enables Yellow and Connect ZBT-1 to run both a Thread and a Zigbee network. Both networks run on the same RF channel.
• Bundled and automatically installed with the Silicon Labs Multiprotocol add-on. This add-on comes with the Thread border router component, as well as with the Zigbee stack. The ZHA integration communicates with the Zigbee stack running inside the add-on.
• This firmware is currently experimental. For more information, refer to the documentation about multiprotocol issues.
• Other terms you may have seen to designate this firmware: multi-PAN, RCP multi-PAN

Overview of Zigbee and Thread firmware options, add-ons, and integrations in Home Assistant.

Chart illustrating the relationships between Zigbee and Thread firmware options, add-ons, and integrations in Home Assistant.

Why is it best to use only one protocol at once?

When we launched Home Assistant Yellow, we announced our intent to release firmware supporting multiprotocol, which allows the device's Silicon Labs chip to connect to both Zigbee and Thread networks with one radio.

This experimental firmware has been available since December 2022. Through extensive testing, we have found that although it works in some circumstances, it has technical limitations that lead to a worse user experience. We now do not recommend using this firmware, and it will be experimental for the foreseeable future. Instead, we will focus on making sure the dedicated Zigbee and Thread firmware for Home Assistant Yellow delivers the best user experience.

There are other key limitations to using Zigbee and Thread simultaneously we explain in this article: About multiprotocol issues.

Why are there multiple firmware options?

You might wonder why there are different firmware options. After all, you could just run the Multiprotocol firmware to use Zigbee and Thread on one device and be done with it. Zigbee and Thread devices run on the same RF channel. If you have a large network, this can lead to bandwidth bottlenecks. For more information, refer to the documentation about multiprotocol support. For large networks, it can help to run the Zigbee and the Thread network on separate devices, for example on a Connect ZBT-1 and a Yellow.

Related topics

• About multiprotocol support
• Zigbee Home Automation integration documentation
• Thread integration documentation