Backing up the MBR
Quite simple, really. Use the ancient and powerful
dd to do this!
dd if=/dev/sda of=~/mbr.backup bs=512 count=1
dd if=/path/to/media/mbr.backup of=/dev/sda bs=512 count=1
The 512 byte sector is composed of three parts:
- 446 bytes for GRUB
- 64 bytes for the partition table
- 2 bytes are persistent
When restoring, these numbers become important. If restoring to a
partition of the exact size, use
bs=512 for backup and restore.
Else, you have to use
bs=446. This is vitally important.