After a bios upgrade my Acer W501 Iconia tab was bricked. Black screen and no working. I have fix the problem 1)Download Acer Bios Driver for W500 from support acer website, unzip and open the DOS folder. rename the file .fd into EAB00x64.fd 2)Create a USB bootable with DOS (I have used a software named RUFUS) 3) Copy the three file present in the dos folder into the usb key 4) Insert usb in your tablet. Put the power supply, lock the rotation and press together WIN BOTTON / VOL DOWN/ POWER ON for 5/10 sec and release. 5) the tablet remain in black screen for 10 mins then automatically restart and all is fixed.