I am having a problem where my nest thermostat doesn’t pre-heat until someone is home because we are using the home/away assist feature that sets the heat level to an “eco” temperature when no one is home. I want to take advantage of home/away assist to save energy when no one is home, but I want scheduled temperatures to override this and begin pre heating on a schedule. As this support post mentions, this used to be the behavior, but a software update changed it.
I contacted nest support and asked them if I could use home/away assist and also have scheduled temperatures override the eco mode. They said no. I asked if I could downgrade the software on my thermostat. They said no - the software is automatically upgraded from the nest servers, and there is no way to turn this off.
I read on reddit about an option to do a factory reset and disconnecting from Wi-fi to disable automatic upgrades. However, I want to also be able to adjust my thermostat settings over the Internet.
Is there a way, perhaps involving some hardware hacking or a firewall, to achieve this by doing a factory reset and blocking the auto software updates?
I found this description of the Nest Thermostat API from 2012. Not sure if it is current and also not sure how to block only software updates without blocking thermostat adjustments I send over the Internet.