Updated October 2026
Data from Amazon and official Nabu Casa and Sonoff sites.
2026 verdict
On a Home Assistant box that mainly runs Zigbee, the Sonoff Dongle Lite MG21 is the better buy of these two USB coordinators: it costs less and can also work as a Zigbee router.
It lists +20 dBm of transmit power and runs on the widely supported Silicon Labs EFR32MG21, and it can be flashed for Thread, although it ships set up for Zigbee. The Nabu Casa Home Assistant Connect ZBT-2 answers with the newer EFR32MG24 chip, a +4.16 dBi external antenna, official Home Assistant hardware that sets itself up, and a Thread border router mode you switch to without reflashing. Both are USB only, work with ZHA and Zigbee2MQTT, carry a 1 year warranty and run Zigbee or Thread, never both at once. Pick the Sonoff Dongle Lite MG21 for a cheap, flexible Zigbee stick, and the Nabu Casa Home Assistant Connect ZBT-2 if you want the official, plug-and-play radio with Thread ready to go.
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| Feature | Nabu Casa Home Assistant Connect ZBT-2 | Sonoff Dongle Lite MG21 | Winner |
|---|---|---|---|
| Price | $65.00 | $24.90 | Sonoff Dongle Lite MG21 |
| Rating | 4.7 | 4.5 | Nabu Casa Home Assistant Connect ZBT-2 |
| Zigbee Router | NO | YES | Sonoff Dongle Lite MG21 |
| Transmit Power | +10dBm | +20dBm | Sonoff Dongle Lite MG21 |
| Antenna Gain | +4.16dBi | +2dBi | Nabu Casa Home Assistant Connect ZBT-2 |
| Zigbee Chip Model | EFR32MG24 | EFR32MG21 | Different strengths |
| Warranty | 1 year | 1 year | Tie |
| Power | USB | USB | Tie |
| Connectivity | USB | USB | Tie |
| Z-Wave Controller | NO | NO | Tie |
| Thread Border Router | YES | YES | Tie |
| Matter Bridge | NO | NO | Tie |
What the differences mean
Chip generation
The Nabu Casa Home Assistant Connect ZBT-2 runs the Silicon Labs EFR32MG24, the newer chip, while the Sonoff Dongle Lite MG21 uses the EFR32MG21. For a Zigbee network today both do the job; the newer chip is the one bought with Thread and Matter in mind.
Thread out of the box
Both can act as a Thread border router, but the Sonoff Dongle Lite MG21 ships set up for Zigbee and has to be flashed first, which owners say can take effort. The Nabu Casa Home Assistant Connect ZBT-2 switches between Zigbee and Thread as official Home Assistant hardware.
Router role
The Sonoff Dongle Lite MG21 can also run as a Zigbee router, so a second or third unit can extend a mesh. The Nabu Casa Home Assistant Connect ZBT-2 is listed as a coordinator only.
Form factor
The Sonoff Dongle Lite MG21 is a light stick with a USB extension cable in the box. The Nabu Casa Home Assistant Connect ZBT-2 is a standing unit with a base and an external antenna, 179 mm tall, meant to sit on a shelf.
Which one to buy if
- you want the cheapest reliable Zigbee coordinator for Home Assistant
The Sonoff Dongle Lite MG21 is the lower priced of the two and runs dozens of Zigbee devices through ZHA or Zigbee2MQTT.
- you plan to add Matter over Thread devices soon
The Nabu Casa Home Assistant Connect ZBT-2 moves to Thread without reflashing, on the newer EFR32MG24 chip.
- you run Home Assistant Green and want zero setup
Owners report the Nabu Casa Home Assistant Connect ZBT-2 is recognised and configured automatically there.
- you want extra sticks to extend the mesh as routers
The Sonoff Dongle Lite MG21 can run as a Zigbee router as well as a coordinator.
- + Rating: 4.7
- + Antenna Gain: +4.16dBi
- - Price: $65.00 vs $24.90
- - Zigbee Router: NO vs YES
Winner
- + Price: $24.90
- + Zigbee Router: YES
- + Transmit Power: +20dBm
- - Rating: 4.5 vs 4.7
- - Antenna Gain: +2dBi vs +4.16dBi
What owners say
Owners of both sticks agree on the part that matters most: they are close to plug-and-play in Home Assistant and keep dozens of Zigbee devices online. Nabu Casa Home Assistant Connect ZBT-2 owners single out the automatic setup on Home Assistant Green, whole-home range from the external antenna and a device that looks good on a shelf, and their complaints are the price over budget dongles and an OpenThread Border Router setup that some found fiddly. Sonoff Dongle Lite MG21 owners talk about value, the freedom to run it as a coordinator or a router, and the included USB extension cable that moves it away from noisy USB 3 ports; their warnings are that getting it onto Thread takes flashing and some effort, and that one firmware update broke OpenHAB support for a user.
Price history compared
Every price change of both, in the same store, so the gap between the two lines is what one costs more than the other.
- Nabu Casa Home Assistant Connect ZBT-2
- Sonoff Dongle Lite MG21
Loading price history...
Frequently Asked Questions
Which is better: Nabu Casa Home Assistant Connect ZBT-2 or Sonoff Dongle Lite MG21?
For a Zigbee-first setup, the Sonoff Dongle Lite MG21: it is the cheaper of the two, works as a coordinator or a router and lists +20 dBm of transmit power. The Nabu Casa Home Assistant Connect ZBT-2 is the better choice when you want official Home Assistant hardware, the newer EFR32MG24 chip and Thread without reflashing.
What is the difference between the Sonoff MG21 and the MG24 chip in these dongles?
The Sonoff Dongle Lite MG21 uses the Silicon Labs EFR32MG21, while the Nabu Casa Home Assistant Connect ZBT-2 uses the newer EFR32MG24. Both handle Zigbee 3.0 and can act as a Thread border router; the ZBT-2 does it without the flashing step the Sonoff needs.
Does the Sonoff Dongle Lite MG21 work with Thread in Home Assistant?
Yes, it can act as a Thread border router, but it ships configured for Zigbee, so you flash it first. Owners say that step can take some effort. It runs Zigbee or Thread, not both at once, the same as the Nabu Casa Home Assistant Connect ZBT-2.
Can either of them run Zigbee and Thread at the same time?
No. Neither the Nabu Casa Home Assistant Connect ZBT-2 nor the Sonoff Dongle Lite MG21 supports dual network mode, so each runs one protocol at a time and a second radio is needed for both.
Who should buy the Nabu Casa Home Assistant Connect ZBT-2?
Home Assistant users, especially on Home Assistant Green, who want the official radio that sets itself up, strong range from its external antenna and an easy path to Matter over Thread.
Who should buy the Sonoff Dongle Lite MG21?
Budget buyers building a local Zigbee network with ZHA or Zigbee2MQTT, and anyone who wants spare sticks to run as Zigbee routers around the house.
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