Thank you for your message.

We would recommend you in installing version A21, as that is the latest version & release according to the time stamp.

Please make sure that the ac adapter is connecting while you are flashing the bios.

Hi , in the search drivers for my product ( Venue Pro 11 7139 core i5) there is  "7139_A16" bios update, but i find, for my own, searching in the dell web drivers,   the "7139_a21" bios update and i tried to upgrade but when the tablet reboot and i check in windows , there still shows that i have the "a16" version bios.

Are something wrong with my tablet? and i tried to install A17 A18 A19 A20 but its the same case,always reboot and shows as A16 version. Only upgrade until A16 bios.

what i have to do??, or A16 is the latest upgrade for my tablet?

My specific problem with this tablet , is the tablet doesn´t power on easily , i have to push the button so many times ,try and try , until for some reason works,  and maybe in some bios update ,are something to fix it, (the main power settings supply for booting or something like that)

thanks for your support

Mine normally takes 2 seconds of pressing the power switch to start, 30 seconds of pressing to force a shutdown (Black screen but only a buzz when pressing the Windows logo at center of the bottom).