Hello,

    I am trying to boot from a USB stick. I used to have "Use A Device" in the advanced startup menu (shift + restart). It is now missing from the menu. This is occurring whether or not a usb stick is inserted. I have read this problem one other place on the forums but had no fix. I have tried disabling secure boot in bios, with no difference. Anyone know how to get my button back? Thanks...

Hi, 

This is mostly related to the UEFI firmware and Hardware security. 

Would you please let me know if you have update UEFI firmware or the driver for chipset and motherboard?

I also suggest you contact the manufacturer to seek for

I have not updated any firmware or driver for chipset. I have a brand new Samsung Book 8