An Xperia phone may end up in a situation where it is stuck in such a way that turning it off in the usual way with the Power key is not possible.
The device manufacturer has created the following backup method for forcing the phone to the off state:
- Press both the Power and the Volume Up keys down at the same time and keep them pressed.
- The display goes black soon. After about 10 seconds, the phone plays the vibrator once (1).
- if you release the keys now the phone restarts itself automatically
- if you want to turn the phone off keep pressing the two keys
- In the next 5-10 seconds (i.e. in 15-20 seconds from the beginning), the phone plays the vibrator three (3) times. Release the keys now. The phone is off.
Use the Power key to turn the phone on, again.