Link: How to Boot Linux ISO Images Directly From Your Hard Drive

Linux’s GRUB2 boot loader can boot Linux ISO files directly from your hard drive. Boot Linux live CDs or even install Linux on another hard drive partition without burning it to disc or booting from a USB drive.

We performed this process on Ubuntu 14.04 — Ubuntu and Ubuntu-based Linux distributions have good support for this. Other Linux distributions should work similarly.

Full article here:
How to Boot Linux ISO Images Directly From Your Hard Drive (How-To Geek)

Link: Repair Your System’s GRUB Via The Super GRUB2 Disk 2.00S2 ISO

Hello Linux Geeksters. As you may know, Super GRUB2 Disk is an ISO image that enables the users to easily repair and restore the GRUB, which is used on the most popular Linux systems, due to the fact that it has support for the most popular file systems.

Full article here:
Repair Your System’s GRUB Via The Super GRUB2 Disk 2.00S2 ISO (LinuxG.net)