GRUB can read ext2 partitions.
This functionality allows GRUB to access its configuration file,
, every time the system boots, eliminating the need for the user to write a new version of the first stage boot loader to the MBR when configuration changes are made. The only time a user needs to reinstall GRUB on the MBR is if the physical location of the
partition is moved on the disk. For details on installing GRUB to the MBR, refer to Section E.3, “Installing GRUB”