boot from usb or cd
df
to determine device mounted on /boot/efi (sda2 in my case)
cd /tmp
mkdir mount-point
sudo mount /dev/sda2 /tmp/mount-point
sudo mount --bind /dev /tmp/mount-point/dev
sudo mount --bind /proc /tmp/mount-point/proc
sudo mount --bind /sys /tmp/mount-point/sys
sudo chroot /tmp/mount-point
dpkg-query -l 'grub*'
to determine which grub packages are installed (grub-efi-amd64 in my case)
dpkg-reconfigure grub-efi-amd64
refers to #129
Sorry - I got the sequence wrong!
boot from usb or cd point/dev point/proc point/sys
df
to determine device mounted on /boot/efi (sda2 in my case)
cd /tmp
mkdir mount-point
sudo mount /dev/sda2 /tmp/mount-point
sudo mount --bind /dev /tmp/mount-
sudo mount --bind /proc /tmp/mount-
sudo mount --bind /sys /tmp/mount-
sudo chroot /tmp/mount-point
dpkg-query -l 'grub*'
to determine which grub packages are installed (grub-efi-amd64 in my case)
dpkg-reconfigure grub-efi-amd64