At this time, we have several distinctly different mobile platforms: Apple iOS, Android, Windows Phone 8, Windows RT, Windows 8/8.1/10, and BlackBerry 10. To say that these platforms handle deleted data differently is not saying much at all. Android and iOS are poles apart when it comes to handling deleted data and recovering information. Windows Phone 8 is somewhere in between, while Windows RT and the full versions of Windows 8/8.1/10 have their own share of issues.
This chapter is easy to write. Recovering data stored in unallocated space in iOS 5 and newer is impossible, even on jailbroken devices. Not even if you send it to Apple, and not if you give them the passcode. Once the data is gone, it's gone. A factory reset erases everything completely and irrecoverably.
A theoretical concept exists allowing you to restore the state of the filesystem to a certain moment in the past. A proof-of-concept tool was...