@ukphil YES !!! this worked also for me!
Months of insecure (is there any virus?? that boots my device twice ???) are past!
thank you very very much !
< " it is a corrupt media database - "/userdata/user-data/phablet/.cache/mediascanner-2.0/mediastore.db" or /home/phablet/.cache/mediascanner-2.0/mediastore.db.
I deleted this db and the double boot/shut down did not happen.">