chroot made easy in 2 commands

Assuming the normal system partition(s) are on a software RAID (otherwise skip this step): make sure the mdadm tools are installed in the Live CD environment (e.g. by executing sudo apt-get install mdadm). Then assemble the arrays:

sudo mdadm --assemble --scan

If using LVM:

sudo sh -ec "apt-get install lvm2; vgchange -ay"

If using bcache:

sudo sh -ec "apt-get install software-properties-common; add-apt-repository ppa:g2p/storage; apt-get update; apt-get install bcache-tools"

Determine your normal system partition. The following commands may be helpful. The fdisk switch is a lowercase "L".

sudo fdisk -l
sudo blkid
df -Th

Mount your normal system partition. X is the drive letter. Y is the partition number:
    Substitute the correct partition: sda1, sdb5, etc. 

sudo mount /dev/sdXY /mnt

    Example 1: sudo mount /dev/sda1 /mnt

    Example 2: sudo mount /dev/md1 /mnt 

Only if you have a separate boot partition (where sdXY is the /boot partition designation):

sudo mount /dev/sdXY /mnt/boot

    Example 1: sudo mount /dev/sdb6 /mnt/boot

    Example 2: sudo mount /dev/md0 /mnt/boot 

Only if (some) of the system partitions are on a software RAID (otherwise skip this step): make sure the output of mdadm --examine --scan agrees with the array definitions in /etc/mdadm/mdadm.conf.
Mount the critical virtual filesystems. Run the following as a single command:

for i in /dev /dev/pts /proc /sys /run; do sudo mount -B $i /mnt/$i; done

Chroot into your normal system device:

sudo chroot /mnt

Reinstall GRUB 2 (substitute the correct device with sda, sdb, etc. Do not specify a partition number):

grub-install /dev/sdX

If the system partitions are on a software RAID install GRUB 2 on all disks in the RAID. Example (software RAID using /dev/sda and /dev/sdb):

grub-install /dev/sda
grub-install /dev/sdb

Recreate the GRUB 2 menu file (grub.cfg)

update-grub

Exit chroot: CTRL-D on keyboard 

Reboot.