By default CloneZilla Live will reinstall grub after restore. In my particular case I am restoring a disk image to same phisical disk without any partitioning/size change. I am expecting to have exact same state as I had right after backup. However, reinstalling grub will render my system to unbootable. If I remove that option [-g] then everything is fine.
My question is in what cases and why CloneZilla ever need to re-install grub when restoring disk image?