Samsung Galaxy S3 mini Factory Reset
When your phone can boot properly You should be backup your important data (such as Contracts\Phone etc.) Go to Applications drawer Tap Settings To Backup and Reset To Factory Data Reset Select Reset Device Tap Erase Everything When your phone fail to start properly Power off your phone Press and hold Volume UP + Home + Power button till the phone turn on Wait for a while, and you phone enter into Recovery mode In Recovery mode, you can highlight item with Volume key and select it using Home or Power key Select Wipe data/Factory reset Select Yes After finished, select Reboot system now Great! The above now totally reset your device and next time you switch it on, it as good as new. However, if you could not get into hard reset mode. you can go to Odin mode and flash a new official firmware. you can refer to: Samsung Galaxy S3 Mini I8190DXALL3 Android 4.1.2 Firmware Download