# Assume partitions as below
# EFI partition: /dev/sda6
# OS partition:  /dev/sda5, /dev/sda8, etc.
# This assume EFI partition is formated as FAT32 with "boot,esp" flags

# After boot using Live CD,
# first, then mount to OS partition, say /dev/sda8
sudo mount /dev/sda8 /mnt

# Check /etc/fstab to list all fs mapping
# Need to double check if any partitions are reformated
cat /mnt/etc/fstab
# check partition uuid with "blkid" to double confirm uuid mapping is correct
blkid

# Next, mount all partitions according to the fstab
# below is just my example
sudo mkdir /mnt/boot/efi-partition # to this and grub-install with "--efi-directory" if your EFI partition is corrupted
sudo mount /dev/sda6 /mnt/boot/efi-partition # or mount to /mnt/boot/efi if EFI partition is not corrupted

# mount all other required paths
sudo mount --bind /dev /mnt/dev
sudo mount --bind /dev/pts /mnt/dev/pts
sudo mount --bind /sys /mnt/sys
sudo mount --bind /proc /mnt/proc
sudo mount --bind /var /mnt/var

# change root to /mnt or /dev/sda8 (os partition root)
sudo chroot /mnt

# grub install
grub-install --recheck
# or
grub-install --recheck --efi-directory=/boot-efi-partition

# update grub
update-grub

# Here, it should work properly!

# If after this, encounter "grub rescue>" or "Emergency mode",
# double check all UUID in /etc/fstab again
# or read the log and find any devices causing timeout

# DONE!!! Happy hacking!!!