Share your experience!
This is how to boot on safe mode
http://talk.sonymobile.com/t5/Software-Updates/Lollipop-New-Features/m-p/955490#U955490
Try to reset stamina like this: first disable stamina mode,after that do the force stop and clear data steps for stamina app under settings-apps-all.Turn off and back on the device and enable stamina.