Sonoff ZBDongle Plus default firmware, limits and flow control

So I bought a ZBDongle Plus ( to use with my Beta CORE when it arrives, but I am a little bit concerned with something from the product description:

The limits of ZBDongle Plus are 21 direct children and up to 40 children (Default values from official firmware). Supported to connect more by configurating yourself.

I can understand the direct children thing, but the absolute limit makes no sense to me since a Zigbee mesh is supposed to support 65535 nodes or something. Is this a concern with this piece of hardware?

Another issue that I identified comes from the manual:

The dongle is pre-flashed with the official Zigbee 3.0 coordinator firmware, which does not support software flow control. The dongle supports hardware flow control, if you want to enable it, please set the dip switch to on, and generate the firmware that supports hardware flow control before running, see the following document for details on how to generate the corresponding firmware.

Is this going to be an issue with CORE? It sounds like, as shipped, the unit is broken since the flow control switch is set to software and the default firmware supports hardware flow control only. Seems very odd. Will CORE handle firmware updates for this sort of thing, or do we have to manage it ourselves? I assume that with a command line we should be able to push the new firmware manually if needed.

The stick will work out of the box. This shouldn’t be an issue. Unless ITEAD changed something, from what I’ve read on this, it’s not a concern. If there are issues, we’ll solve them programmatically.


The 40 children statement is weird and worrying. Even if they meant 40 children off each direct child . Or maybe that is how the thing expands with 40 children off each child again ?

Will we be able to update firmware directly on CORE? (Perhaps not immediately, but at some point in the journey?)

Yes, we’ve been working on this already. He’s been working on it since the Z-Wave firmware issue. It’s something that may happen sooner than you think.


Firmware updates for IoT devices are a real problem in general. Most companies never patch even fundamental flaws in their products, and the ones that do, tend to provide their updates in a very poor way. Look at Aeotec who provide a weird Windows executable with the update built into it that only works on their own Z-Stick 5. Worse, because it is just lazily built on the SiLabs SDK, it does not understand what device types are on the network and provides little support to identify what device you are updating.

I know that this is not CORE’s problem, but anything that we can build to help correct this will be amazing.

I’m no expert but I’ll offer what I think this means.

If you look at your HE’s http://YourHubIPHere/hub/zigbee/getChildAndRouteInfo you’ll see 3 sections: Child Data, Neighbor Table Entry, and Route Table Entry. I think the Child Data is the 21/40. As long as there are routers/repeaters in the Child Data/Neighbor Table I think the Route Table will grow to accommodate the bazillion devices.

That’s great! :slightly_smiling_face: Even though it’s not that hard to upgrade the firmware outside CORE as well…

This is the exact reason I still have all my lights on the Tradfri hub, so they are always up to date. If CORE could update everything that would be amazing and make it a game-changer in my opinion.

The IKEA firmwares are available in a public location and can be used for updates, so yes, that is done on CORE. There are also plenty of others, but all, no. Both Z-wave and Zigbee have limitations here, mostly due to vendors not providing firmwares to be included. Over time we will work on getting more of those we don’t yet have. Some which do exist we can’t include, yet, due to licensing issues, but there will be ways for users to add them manually. This will probably be an ongoing battle to keep up with…

Oh, and I’m all for writing extraction tools for firmwares provided in strange formats, but if it can’t be official it’ll be more of a community thing. I’ll help out where developers need help and we’ll find a way to make these things into standardized plugins.