Home Assistant Connect ZBT-1 issue and replacement

We’ve found an issue in Home Assistant Connect ZBT-1 that has affected a small number of customers, which appears to be the result of a faulty part incorporated in the most recent batch of ZBT-1 devices. We want to make sure everyone can get a replacement ZBT-1 and ensure they are covered far into the future.

Though Home Assistant SkyConnect is identical to the ZBT-1 under the hood, it is not affected. The design is not what’s at fault, but instead, a defective voltage regulator that was used in this specific batch that is causing the issue. When a ZBT-1 is inserted into certain USB-A ports, the voltage regulator can fail, fully bricking the device. We used high-quality manufacturing and quality control in this and previous batches. We are undertaking an investigation to find out how this could happen and most importantly, to avoid a repeat of anything remotely similar in the future.

We’re sorry for any inconvenience this may cause you. Below are details on our investigation, how devices are affected, and the replacement program.

Background

Around a month ago, we were contacted about one of our latest (and recently rebranded) Home Assistant Connect ZBT-1s not being detected and showing a small mark on the housing. A couple more similar issues were reported, and we began a dialogue with the small number of people who were affected, having them send us the devices to test.

Circled in red the deformation on the case and the board showing the failed chip

When we opened them, we found a dead voltage regulator. The mark in the outer casing is a sign that it overheated and failed. All of our devices are certified by CE and ROHS, and the plastic shell has been designed not to combust. This is a real-life demonstration of just how important this certification is and why we take that step.

We replaced the voltage regulator on the devices we tested, and the devices sprang back to life. We found our culprit, but why was it failing? As mentioned, the SkyConnect internal design and the manufacturing were effectively identical to the ZBT-1, and we received no reports of any such failures in the literally tens of thousands of them in the wild. In manufacturing runs there is always a little variance, and in this run, something went wrong with the voltage regulator that was sourced - again, we’re looking into this.

It took us a couple of weeks to replicate the problem with our own units. We went down some wrong paths, but eventually found it was triggered only by certain devices, specifically certain desktop PCs (internally, we have only found one desktop that causes this failure). We have not observed the failure occur when the device has only been connected to a Home Assistant Green, Raspberry Pi, or even a Mac. If you have plugged your ZBT-1 into a different device, specifically a desktop PC, and it is not recognized by that system, inspect it for this deformation pictured above. Obviously, we want you to be able to use the device with any hardware, and even if only a small number of devices from this batch have reported issues, it is still unacceptable to us.

Pausing sales

We have asked our distributors to pause sales and return all stock. For the next month, you will see “Out of Stock” banners, and if you are attempting to get a replacement device for a failed unit, this will not be possible until production is resumed.

We are working to have replacement ZBT-1s shipped by early November.

Replacement Program

If you have purchased Home Assistant Connect ZBT-1, we are working on a replacement program. This program will see Nabu Casa provide a replacement device free of charge for a period of 60 months (5 years) for verified purchases. Regardless of whether the device has failed, we will provide a replacement upon request.

It is a core value of ours to do things as sustainably as possible, and that’s why we’ve provided such a long coverage period. We want to give owners with working ZBT-1s, who do not expect to use the device in a different system for the foreseeable future, the ability to keep it operating with peace of mind.

If it’s working, keep it plugged into the device it’s working with, and don’t worry about a replacement until you need it. If you need or want a replacement, please contact the seller where you purchased your device, and they will arrange the return process and replacement. Replacement devices are expected by early November, and we will be prioritizing people with non-functioning devices.

Conclusion

We’re sorry for the inconvenience and any disruption to your smart home. As someone who uses Zigbee in their home, which many smart devices rely on, I would hate to have it out of commission.

Worse things can happen, but this has been a gut punch. All our work at Nabu Casa is to fund the development of Home Assistant and support the Open Home. Issues like this eat into our time, and rob our users of new and great things. Ultimately, we’re going to take this setback as a chance to prove we stand by our values and do the right thing.


This is a companion discussion topic for the original entry at https://www.home-assistant.io/blog/2024/10/02/connect-zbt1-issue-and-replacement
8 Likes

Hardware is hard.

More importantly, you are handling this in the most transparent, responsible and customer-friendly way possible.

Looking forward to the post-mortem on WHY the component fails!

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1000000%! It sucks that things have gone wrong - but things do go wrong and it’s how you deal with it that matters. And Nabu Casa have dealt with this marvellously :blush:

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Yes they have.
Hell, I’d say they were *too generous. A 5-year return period doesn’t safeguard against the scammers who run into an issue when their warranty runs out. I’d have extended the warranty period and stopped at that.

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Kudos for the way you are handling this, and for the full transparency. Thanks.

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Good time to consider making a next-generation Home Assistant Connect ZBT-2?

  • Bump to a newer EFR32MG24 or newest EFR32MG26 chip?
  • Add an external antenna?
  • Add an electromagnetic shielding cover to EMF sensitive components on the board?
  • Include a longer shielded USB 2.0 extension cable?

Maybe also make ZBT-2 in different colors to separate which firmware is preflashed from factory?

  • Red color cover for Zigbee preflashed?
  • Orange color for OpenThread (Thread) preflashed?

Save the color blue for Bluetooth and perhaps use purple color for Z-Wave?

Regardless I think it would be good idea for a complete hardware refresh with newer radio chip and external antenna.

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Is it absolutely certain this only affects a ZBT-1 batch?

I checked my Home Assistant SkyConnect or atleast that’s what i think it is, i bought it on June 11 this year, two days before the ZBT-1 announcement.
it shows a faded area in the same placement, and has only ever been connected to a Home Assistant Green.
It’s still working and has worked flawlessly since purchase, but it concerns me that it also shows this faded area.

Do all units have this faded area on top of the regulator or only ones that have this defect?

You shouldn’t be impacted by this based on when you bought it. As long as it works, it should be fine - what you want to watch for is warping of the plastic itself.

Quick edit to add: It will absolutely stop working if you are impacted. :slight_smile:

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I’m impressed by both the level of effect you put in to diagnosing this issue and the steps you’re taking to assist impacted users. Kudos!

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I would like to know how the customers contacted Home-Assistant to make the complaint. I tried to get a response from Home Assistant for several months via twitter/Github for a faulty Home Assistant Connect, but support did not exist and the thing when in the bin. Basically money down the drain!

I don’t have one of these but must say I am deeply impressed by the way you handle this.

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Is batch 232401 affected? I have an unopened box here that I’ll open soon.

If you know which batch is affected, why not just tell us? Especially as the boxes have big batch stickers on them, batch numbers aren’t obscured at all.

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Yeah, batch 232401 is the one affected, the stick immediately got super hot and melted the plastic on the spot.

Really stupid of you to ask people to experiment with melting their sticks instead of just telling people which batches are defective.

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There is no batch specified because it is all ZBT-1s - if you have a ZBT-1, assume it is faulty. I’m not sure we asked people to test things, though, we said if it’s still working then get a replacement when it stops working. I’ll talk with the team about getting wording corrected if you let me know what led you to believe that we were asking that, though! Definitely don’t want to give that impression at all.

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Quotes from the article:

the most recent batch

defective voltage regulator that was used in this specific batch

Obviously it is logical to think you are talking about a specific batch when you explicitly state so.

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Gotcha, that’s fair. I’ll let them know. :slight_smile:

How do you tell if you’re affected? Is the device still recognised, but nothing connects, does the device stop being recognised as USB, etc.?

I bought mine from Seeed Studio in China (I believe this is the official seller for those of us located in New Zealand) a few months ago.
Was just wondering about the “return process”, since the postage to here was USD26, which is basically the same price as another ZBT-1. Will we need to pay shipping to return these, does anyone know? Or perhaps we’re too soon in the remediation process for these sorts of edge-cases to have been considered yet?

I agree my sky connect crashes my system at least once a week. My old Conbee never once crashed it.