Nest Software version 6.3-5 Bricked 3rd Gen Thermostat

[jdsullivan123]

I have had 2 of the Nest Learning 3rd gen Thermostats for about 5 years.  One of them is still running 6.2-27 (the last known update Google shows) and is great.  The other, updated 3/17/25 to version 6.3-5 and bricked the device.  no longer would it communicate with the app or connect to wifi.  i tried everything including resetting the device and it wont connect to any wifis.  i had to buy a new one yesterday after no hvac upstairs after the reset wont even allow it to work at all now.  this update isnt even showing as available on the web.   I am not happy.  there was no practical reason to need to spend money on these again.

[Gils]

Yeah while I am not experiencing the woes you are having with this software upgrade I am finding it very odd that there isn't any official information whatsoever about this update? Google have not posted anything.  Does anyone here have some extra information?

[jdsullivan123]

Agreed. I keep waiting to see it as an update on their list. And nothing. Very odd 

[Gils]

Yeah I am now actually starting to have some issues with it as well. Nothing as severe as what you are experiencing I think but it has had one spontaneous reboot just this morning and it has also disconnected from the nest network twice. Now the latter is not unusual, this happens from time to time but the reboot, I have never had a restart like this before. 

I have tried talking to some support people mainly to ask about this update and of course no one can tell me anything. The fact that there is nothing whatsoever from Google is not just odd it is suspicious to me; I am now 15+ years using Google gear of all sorts and it has always been common practice by Google to post release notes about any software/firmware upgrades no matter how big or small. The only thing I would normally think of is that this is some sort of a ghost update that didn't actually change anything BUT seeing we are having issues I am not sure thats the case. 

I have escalated it with nest support team just to get to the bottom of things. Not holding my breath on having much response though 😉

[jdsullivan123]

our issues started the same, with it rebooting randomly.  then wifi was gone and following support suggestions to disconnect it and re set it up caused it to never connect again to even run heat/ac on the device bc once you wipe the device, it requires Wifi to even set up to work.  so in following their instructions, it locked me out of using it completely.  had i just left it alone it would have at least worked without the wifi and app for a while and not forced a Home Dept same day delivery of the new one so we would have heat at night.   

this was a forced upgrade.  im not happy.  cost me $125 for a new (and not even learning) thermostat.  i set my own schedules on my learning anyway so i didnt pay up for the learning one this time.  

[SteverB_26]

My heating stopped working... Been checking over my furnace and found that the W1 wire is not getting current when heat should be on (there should be current there). Not sure how the upgrade would affect that, but who knows????

Trying to find my old thermostat (an Ecobee3)... but I haven't used that in over 5 years... not sure if I can find it... sigh!

[MotleyC]

My thermostat got the update on the 18th and now I have noticed that it is randomly setting the heat to 90 degrees or setting it down to 60. It seems to happen every few days and I only know when it gets really warm or cooler than normal. Never had an issue before the update

[brothabman]

I am having an issue - the updated pushed thru about 3 days ago and now one of my thermostats won't cool anymore. 

[gkhicks]

Same here... however, only one of the three at one house will no longer call for cooling!  I had to replace a single unit at another location after the update because of a similar issue...but the unit was throwing heat vs cool.  I am beginning to believe that Google screwed the pooch on this firmware update!

[Likaybai]

I recently bought a used Nest Learning Thermostat (3rd Gen) from Goodwill for $19.99, though it didn’t come with the base (I found one on eBay for $13.98). After replacing my Honeywell thermostat and installing the NLT, the setup went smoothly. It automatically updated to firmware version 6.3-5 once connected to Wi-Fi. So far, it's been running without any issues and I’ve successfully integrated it into Home Assistant.

[aalvino73]

So frustrating. I had this happen to me 4 days ago. I was having a large gathering that evening when I woke up to a cold house.  I have 2 of the same 3rd Gen that both stopped working on the same day. Freezing cold house with a bunch of people coming.  Agreed 100% that there was no reason for this. There, at the very minimum, should have been a notice sent that they will stop working.  I have gone back to old programmable non-wifi thermostats.  

[carl310]

My thermostat updated this evening (found the update timestamp in the nest app), and at first I just noticed that it had lost its wifi connection. Not just the connection, it didn't remember my wifi ssid or password. So I restarted it, and put in the wifi details again. After about an hour I walked by it and noticed it had lost its wifi credentials again. Now usually when wifi goes down, it will say it lost wifi but then will regain the connection when my router comes back online. My wifi has been working fine the entire time.

Haven't tried using cooling yet which seems to be everyone's current problem, but that is because it is 40 degrees outside and I don't want to run the condenser in those temps.

[Djm2]

Having a similar issue. After update it’s stuck in an update loop. I can no longer use the thermostat. 

[Dunlapjc]

Same exact situation, have 6 3rd generation thermostats...
5 are working.  
1 is stuck in an update loop.
So frustrating

[Djm2]

My nest 3rd gen automatically updated about 1 week ago and now it’s stuck in an update loop. After some research it seems to be a known issue. People are having the same issue with the recent Nest 3rd gen update. 

https://www.googlenestcommunity.com/t5/Nest-Thermostats/Nest-Software-version-6-3-5-Bricked-3rd-Gen-...

[trivial0921]

My 2 3rd Gen Nests worked great for nearly 10 years, in 2 different houses, until the 6.3-5 update. My current house is heating only (oil-powered steam radiator / boiler system) and the Nests worked great for nearly 3 years here, until this update. Now, when the desired heating temperature is reached, the Nest correctly displays that it isn't heating any more, but the boiler starts getting continual on and off signals in quick succession, for many minutes at a time.

After going back and forth with Google tech support, they basically told me I had to get a new unit. I bought a 4th Gen, updated to the latest software, and then had the same exact problem.

Sadly, at this point, I have returned the 4th Gen Nest and put back the 'dumb' Honeywell thermostat that came with the house. I miss the smart thermostat and hope to hear about a fix so I could reinstall my perfectly fine Gen 3 units, but do not want to damage my boiler in the meantime...

[kukraw313]

nice ty for sharing