Wish to install Ubuntu 16.04 LTS on a MacBookAir6,2 (dual boot with macOS Sierra).
I created USB stick with Ubuntu image.
brew cask install unetbootin
I pressed at boot ALT key and entered "Install Ubuntu" and receive the error
error: premature end of file /casper/vmlinux.efi alloc magic is broken at 0x7a2d93c0: 7a179da0 aborted. press any key to exit
When you google this error message there are no hits. I configured a firmware password on my MacBook Air. Because of security I don't wish to undo that.