I don't know if there is anything bogus about Hall sensor for magnetic flip cover, I'm using a flip cover with my Walton Primo NX. It never locks when I flip. But recently I bought Symphony Tab T7pro included their flip cover with magnetic buckle. It locks when I flip the cover and turns on the display when I open the cover. I checked on covering the proximity sensor only but did not locked, it doesn't sense there. I tried with a hard board, but nothing happened. then I tried both reversal and repositioned that original flip cover and still no locking. It's locking only when I flip that original cover on actual position and direction. And besides, there is no such proximity-locking software installed on it. I think there is a Hall sensor placed in there, cause I read about how Hall sensor works and also read its applications.