Commission Nest Wifi as Thread Border Router on an existing Nest Hub (v2) network

[danstiner]

I recently purchased a Nest Wifi router to add to my existing Google Wifi mesh, in part because it is advertised to act as a TBR (thread border router) since version 14150.376.32 and I wanted to extend the range of my thread network to cover the entire house https://support.google.com/googlenest/answer/13800967?hl=en. Took a few attempts to setup but is working fine now as part of the wifi mesh.

However, the thread side is not working as I'd expect. The nest wifi did not join my existing Nest Hub (v2)'s thread network. Instead it's creating a new thread network every few minutes, like it's stuck spinning. Both devices were setup through the Home app on the same Android phone.

I can confirm I have two different thread networks both through Home Assistant and querying mDNS directly:
-  Nest\032Wifi\032Router\032#D991._meshcop._udp.local. can be reached at c158604385632c4a5e4b8e68687dcf65.local.:49152
- Google\032Nest\032Hub\032(0cba)._meshcop._udp.local. can be reached at fuchsia-d88c-7959-aa47.local.:49154

I've tried factory resetting the nest wifi a couple of times, the pattern seems to be:
- After factory reset + setup, it will not act as a thread border router at all
- After rebooting once, it will act as a thread border router and commission it's own new network every few minutes, like it's stuck in an error loop
- After some time, it will stop commissioning a new network id and stick with one

Should I return the nest wifi? I bought it expressly to expand my thread network coverage, and it's not doing that.

[MichaelP]

I escalated this since, as far as I can tell, this is a bug in the Nest WiFi Router Thread (or, possibly, the Nest Hub Thread) implementation. 

[ByronP]

Hi danstiner,

I understand you're having trouble extending your Nest Wifi Router's coverage and using it as a Thread Border Router for your Nest Hub (2nd Gen). It sounds like it's struggling with commissioning, creating a new network ID, and getting stuck in a spinning loop. I really appreciate all the troubleshooting you've already done, and thank you @MichaelP for escalating it. Let's work together to find a solution.

The team would like to learn more about this behavior. When you get a chance, please fill out this form and let us know when you’re finished. We’ll have someone reach out to you via email from there.

Regards,

Byron

[danstiner]

Thanks Byron and Michael. I've submitted the form.

I'll add that it has stopped spinning in a loop after leaving it for a couple of days. But the wifi router is still setup as a separate network/fabric. I expected it to join my existing Nest Hub's thread fabric instead of creating a new one. I set it up through the Home app on android, and confirmed my phone had the credentials for the Nest Hub as I set it up from the same phone.

[ByronP]

Hi danstiner,

Thank you for your prompt reply. I appreciate all the detailed information.

I received your form; a dedicated team will reach out to you there for further instructions.

Please keep an eye on your email for any updates.

Regards,

Byron

[danstiner]

I was able to join both Hub&Router to the same Thread network finally. I believe the issue was a bug with how Thread credentials are stored to Google Play Services. Factory resetting both devices then deleting storage for Google Play Services and setting up both fresh caused them to join the same Thread network. I got a notification about thread credentials being stored to my google account that I've never seen before as part of that setup, making me think how thread credentials are managed has changed since I originally setup the Hub and mine were somehow not migrated correctly, and deleting play services storage helped reset things.

This created a new network, so I'll have to re-commission all my Thread client devices which is annoying. Deleting play services storage also wiped all my saved credit cards etc which is also annoying. But at least it's working!

I will keep engaging with support to see if they are willing to escalate this bug for an engineer to look at, but so far their messages have been confusing and contradictory, I had to figure this out on my own.