Thanks for the error code decoder ring. I'm seeing now that the issue had nothing to do with my home network, which has been stable and maintained connections to all other non-Nest devices for years. The P002 error held the key: There is a secondary ad-hoc network that Nest attempts to create (and to which the user has no direct access or influence) - that is what was failing. Since the issue is with a non-user-facing error, all the junk about resetting routers and such is, of course, a red herring. So there is no real solution, and one simply has to start all over with full factory resets. Terrible design from a usability perspective. But such arcane concepts as "usability" have long gone by the way-side in software circles. So I do understand why Google inflicts this mess upon its users. Hopefully no one else will develop a product with good usability to cut into Google's market share... 😉
