If you use a Zigbee router powered by the Texas Instruments CC2652R or CC1352R chip, you might want to consider updating its Z-Stack firmware. The list of devices making use of the aforementioned chip include many niche products such as the Electrolama zig-a-zig-ah! (zzh!), Slaesh's CC2652RB stick, and Tube's CC2652P2 USB Coordinator. It is also found in the more recognizable SONOFF's Zigbee 3.0 USB Dongle Plus (ZBDongle-P), which many use, due to its broad availability and low price.

What is a Zigbee router?

Before proceeding, I would like to point out that this update only applies to routers and not coordinators. Routers are used to improve the range of a Zigbee mesh network and are frequently also found in mains-connected devices, such as light bulbs and smart plugs. The coordinator is the actual brains behind the Zigbee network. All your devices are bound to the coordinator, and flashing it with the wrong firmware will make your Zigbee network go up in smoke. You have been warned.

Additionally, you must verify that you are running at least Zigbee2MQTT 1.28.3. While your router will still function under an older version, you will not have access to the settings mentioned in this article. To find out which version you are using, you can either check your container or add-on, or navigate to the About section of the settings found in the Zigbee2MQTT Dashboard.

Why should I flash the new Z-Stack firmware?

The most pertinent addition to the 20221102 release of the Z-Stack 3.x.0 Router Firmware, is the ability to adjust the transmit power. Certain routers, such as the SONOFF Zigbee 3.0 USB Dongle Plus mentioned above, are capable of more than what you might be experiencing. It has a default output power of 5 dBm, even though it is capable of 20 dBm. Increasing the output power will obviously also increase the device's overall power consumption. Despite that, it might be worth checking the settings in your Zigbee2MQTT Dashboard if you have been experiencing a weak signal strength.

Updating the firmware of a Zigbee2MQTT router

Updating the firmware of your Zigbee router does require you to attach it to a PC, as OTA is not supported. While there are tools that supposedly help you enter the bootloader mode, I have found that the following steps lead to the highest success rate, when attempting to flash such a device:

• Download the correctfirmware for your Zigbee router. I cannot stress this point enough. If you are unsure which option to choose, don't do it. Selecting the wrong firmware can brick your device. In addition to the firmware, I recommend using the ZigStar GW Multi tool to flash it. Launching it with administrator privileges might be required.
• If necessary, remove the casing of your router. The Zigbee 3.0 USB Dongle Plus from SONOFF has two screws on either end, which can be removed using a small screwdriver. Once removed, the board can be slid out. Other routers might have a snap-fit plastic case.
• Push the button labelled boot and insert the device in to a free USB port on your PC. Keep the button pushed for ~30 seconds to assure that it is ready.
• The device should be picked up by the ZigStar GW Multi tool. You can now flash the firmware.

Is it worth updating a Zigbee router's firmware?

If your Zigbee mesh is working fine as it is, there is no feasible reason to risk disrupting anything or bricking your router altogether. This update is recommended for those who might be struggling with link quality issues and don't know whether they are getting the most out of what they have.