Please refer to below Manual Factory Reset instructions.
1. Disconnect the power cable from Z mini device.
2. Press & hold down the small button on the Z mini and reconnect the cable.
* make sure the button is being pressed until the Android Recovery page shows up.
3. The Android Recovery page will show up.
From here, one single press on the button (on the Z mini) will move down a menu, and press & holding the button will select the menu.
4. Select 'Wipe data/factory reset.'
5. Select 'Factory data reset.' When data wipe is completed, it will show on the bottom left corner.
6. Select 'Reboot system now' menu to apply the factory reset.
IF this doesn't answer your doubts or you want to search more information,
Please take a look at threads in our forum FORMULER FORUM Or click TAGS on the right side of this page.