Rescue System

If your system fails to boot, you can use the "Enable/disable rescue mode" option to access the hard disk. 

The rescue environment relies on Rescatux. After turning it on, boot into it, and first locate the original hard disk by entering the command:

lsblk

You'll see disk devices listed. For example, /dev/sda1 should match your hard drive's size (e.g., 50GB).

Next, mount the device to a folder. To mount it at /mnt, for instance, run:

sudo mount /dev/sda1 /mnt

Make any required changes.

Turn off rescue mode once you're done.