I tried to clean install my Venue Pro 8 3845, I cleaned the internal HD with the Diskpart tool from the command prompt (I bootet from recovery), after that i restarted and wanted to boot from a USB stick with windows 10 64 Bit on it, the stick is bootable (I did another tablet before). But it seems the venue doesn't bother what I do or set in the uefi, It always says "internal hard disk drive not found". I selected several .efi files to boot from the stick in the settings, nothing worked. Any idea what I am doing wrong?
Did you get the Windows 10 usb key from Dell? If not, you may want to contact dell support by phone to obtain on for your tablet.