For people who don't like clicking the link, or watch the whole 8min video here the description from YouTube:
1. SAFE MODE
. - Safe mode allows you to turn on the device with third-party apps disabled. Then you can easily remove all apps that maybe causing a conflict or a software problem.
. - First way to enter Safe mode, pres the power off button. From the Power off menu, tab and hold "Power off" option, until you see "Reboot to safe mode" menu.
. - Second way - turn off the phone. Turn it on and when you see the Xperia logo, press and hold the volume down button until the phone load Safe mode.
. - To get out of the safe mode, simply turn off and turn on the device.
2. HIDDEN TEST MENU
. - To enter into Test menu, open the Dealer app and enter this code: *#*#7378423#*#*
. - From here you can test Cameras, Microphones, Loudspeakers, Earpiece, Touchscreen, Display, GPS, Accelerometer, Proximity switch, Pressure sensor, Compass, Gyroscope, etc. Also you can find information for the Firmware, SIM lock status, Working bands, etc., and do a Factory reset (Reset customization).
3. HARD AND SOFT RESET
. - Soft reset - Because, for this models you can't remove the battery, Sony provide you physically reset button. You can use it, if your device freeze. This will not affect your data and settings.
. - If your device crashes, freezes or if you have a problem with the Android OS, you can perform a Hardware reset. This will delete all personal data and will set the device into factory settings.
4. DEVELOPER MENU
. - Developer Options have many features for app developer to test an app on their device from PC via ADB. From this menu you can activate USB Debugging mode. On more recent versions of Android, the developer options have been hidden.
. - To enable Developer options, go to Settings - About phone. Navigate to the bottom and you should see Build Number. Now tab it 7 times and ... "You are now a developer."
5. RETAIL DEMO MODE
. - In this mode the phone start demo video and do this every time it goes to sleep mode. Older version of Android have a bug, that allowed to change the screen lock if the phone has Lock screen. For the newer version you can't enter "Retail mode" if the phone is screen locked.
. - To enter and go out this mode, enter this code: *#*#73556673#*#*
