[Q] how to stop autoupgrade and go back v2.0 (hd+ stock) topic

Hi everyone,
Now my nook hd+ is in stock rom v2.2. But since this version was updated, my nook is very hot (the left bottom) and the battery lasts shorter (just 2.5hours screen on) and sometimes doesn't display battery percent correctly.
Can you help me the way going back the old version and stop autoupgrade to v2.2?
Thanks