Fog is doing something wierd to my MBR

[Martin Fryd Wochner]

so i have 80 identical machines, the only difference on them is the order its plugged into the sata…
i made an image for a:
Grub loader
Linux Mint 12 (1 partition, 1 hdd) using the Multiple Partition Image ( single Disk) image type.

the image works fine on the first 3 computerss, but somehow the deployment destroys the MBR on the rest of the computers, leaving me with i have to fix it manually with a live cd, and reinstalling grub on each of the machines…

why does fog do that, and can i fix it somehow?