The answer is "Ask the maker."
In some tablets, you have to install apps after the factory reset. I can't guess how many no-name tablets I've encountered that are wonky after a full reset. Thankfully we learned about this sooner than later and at the office will not pick up any no-name tablet.
Bob
The G-sensor calibration program(under the settings menu) of my Android 4.0 table doesn't work. It even disappeared after a factory reset.
How to recover it?

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