sudo fsck.ext4 /dev/
sudo mount /dev/ /mnt
# If boot partition:
# sudo mount /dev/ /mnt/boot
# Efi:
sudo mount /dev/ /mnt/boot/efi
# 4
for dir in /dev /dev/pts /proc /sys /run; do sudo mount --bind $dir /mnt$dir; done
# Wenn wir efi haben:
sudo mount --bind /sys/firmware/efi/efivars /mnt/sys/firmware/efi/efivars

sudo chroot /mnt /bin/bash

# Optional:
df -h
apt update && apt upgrade
grub-install /dev/sda
update-grub
update-initramfs -u -k all

lsblk -f
cat /etc/fstab
# CHECK FOR ALL UUIDs!

exit
sudo umount -R /mnt/


# Do a fsck on the filesystem! In the end, if we currentrly recover.
sudo fsck.ext4 /dev/