This worked for me on my MPB 2015
apt-get purge shim mv /boot/efi/EFI/ubuntu /root/ubuntu-efi.bak #backing up just in case grub-install /dev/sda1
This worked for me on my MPB 2015
apt-get purge shim EFI/ubuntu /root/ubuntu- efi.bak #backing up just in case
mv /boot/efi/
grub-install /dev/sda1