If your tablet is stuck on a black screen with a Meta Mode/Fastboot Mode message on the lower left side of the screen, all that is needed is a quick restart. Hold the Power button on the tablet for 10-15 seconds until the device restarts
In case this does not work, you may also reach out to Booky Merchant Support through Viber. Kindly give them all the information regarding the issue so they can better assess the solution.