The board I bought from the official website is SABRE Platform for Smart
Devices, i.MX6DL. When I run android 4.4.3 using i.mx6 BSP ,I found four
touch keys on the bottom of the touch screen didn't work. How can I use
these keys. I geussed the four keys are "home", "menu", "return" and
"search". Attachment is the photo of the keys on board(or on screen).