A kind reader of this blog pointed this out to me:
It appears that Longhorn has a UEFI exploit, related to Windows surface devices. I’m not sure yet if it requires ARM or Intel system, and I don’t know the details of the exploit, it appears that it has not been released.
https://twitter.com/never_released/status/723144680507117568
https://twitter.com/never_released/status/723146681940738055
https://twitter.com/never_released/status/724506763240833025
https://twitter.com/never_released/status/725355698431905793
https://twitter.com/never_released/status/725355698431905793
https://twitter.com/never_released/status/725034729599307777
https://twitter.com/never_released/status/724984950584446976
https://twitter.com/never_released/status/724506763240833025
https://twitter.com/never_released/status/723896207475675136
https://twitter.com/never_released/status/723796480281182208
Firmware Security 