This is the correct way to hard reset (factory reset) BlackView Oscal Pad 7
First turn off the Tablet
We will use the power button and the volume down button
Press the buttons in order
When the Oscal logo appears, release the power button then release the volume down button.
Use the Volume Up and Volume Down buttons to navigate.
and select Wipe data/factory reset.
Press the Power button to confirm the selection.
Now Select Factory data reset, and press power button for ok.
And wait until you see Data Wipe Complete.
Now select Reboot system now
If the device takes a long time to restart, turn it off and then turn it on.