How to restore MBR on a separate /boot partition?

Mon Apr 8 16:06:59 UTC 2013

Since I was unable to install F18, I would like
to revert back to F17 that I have restored from
backups, the following partitions:

/ (root)   /dev/sda10
/boot      /dev/sda9

What I have left to do is to restore the MBR
on /dev/sda9 /boot partition.

I have a separate MBR installed on /dev/sda
drive which is the master MBR for multiboot
OS, which is working fine.

What steps can I use to accomplish this?