boot repair update grub

1.detect your disk

2.change you root

sudo chroot "/mnt/boot-sav/sda1" dpkg --configure -asudo chroot "/mnt/boot-sav/sda1" apt-get install -fysudo chroot "/mnt/boot-sav/sda1" apt-get purge -y --force-yes grub*-common grub-common:i386 shim-signed linux-signed*

3.remove grub2 from /boot/grub

choose
yes

4. install grub force

sudo chroot "/mnt/boot-sav/sda1" apt-get install -y --force-yes grub-efi-amd64-signed shim-signed linux-signed-generic