Sorry if this has been covered. HDX 10" and 7". Backup battery on 10". Updated to 17.1 ( did it with last update as well). All went well. 10" first, then 7". Turned system off. When I went to fly this morning, the 10" would not power on. Had to to momentarily disconnect the main connector (45 pin?). After that, all is well. Any ideas? Something to do with backup battery maybe?