I have a gpt /dev/sda.
run boot-repair and I got this:
WindowsEFI detected. Please disable BIOS-compatibility/CSM/Legacy mode in your UEFI firmware, and use this software from a live-CD (or live-USB) that is compatible with UEFI booting mode. For example, use a live-USB of Boot-Repair-Disk-64bit (www.sourceforge.net/p/boot-repair-cd), after making sure your BIOS is set up to boot USB in EFI mode.
booted from USB and I got this:
Boot-repair-disk can't repair: Locked-NVram detected