chroot and fix grub

gistfile1.txt

# https://wiki.manjaro.org/index.php/Restore_the_GRUB_Bootloader
# https://wiki.archlinux.org/index.php/GRUB#UEFI_systems

sudo su
lsblk -f 

# mount rootfs to mnt, ext4
mount /dev/sda1 /mnt
cd /mnt/

# mount boot to mnt/boot, vfat
mount /dev/sda3 /mnt/boot

# mount userfs to mnt/home, ext4
mount /dev/sda4 /mnt/home

mount --rbind /sys sys/
mount --rbind /dev dev/
mount --rbind /run run/
chroot /mnt

cd /boot
grub-install --target=x86_64-efi --efi-directory=/boot/efi --recheck
sudo update-grub