Backing up the MBR Revision as of Sunday, 20 December 2015 at 19:56 UTC
Quite simple, really. Use the ancient and powerful dd to do this!
Backing up
dd if=/dev/sda of=~/mbr.backup bs=512 count=1
Restoring
dd if=/path/to/media/mbr.backup of=/dev/sda bs=512 count=1
Notes
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.