For some reason one of my nest thermostats - 2nd Gen - is stuck on a black screen with a green flashing light. I thought it was stuck in a reboot mode after a software update, so I unplugged the battery terminal and reconnected it. That saw it boot up, but it only lasted a week and is back to the same blacked screen and flashing light. The same process did not resolve the issue a second time around.
I have tried changing from USB, not change and also placing it on an equivalent, functional base of one of my other nest thermostats, still no change.
Ive tried holding it down for 10 seconds but that did nothing. Has anyone got any ideas? Has it got corrupted during an install?