Using grub-legacy solve my problem, thx Fernando.

I’ve just use this live cd :

[url]http://sourceforge.net/projects/boot-repair-cd/[/url]

With this options : remove grub2 and install grub legacy.

All works fine, reboot, up new image, and down on all our PC.

I will try the grub-legacy instead of grub2 option, it was the next i have to do.

i’ll tell you results.

I have the same problem, deploy linux images of ubunutu 11x or 12 (the upload work fine).

after task complete the pc reboot constantly.

If i repair the mbr with an boot repair live cd, pc works fine.

But i have too many pc to deploy …

I still investigating this forum to find solutions.

(serveur on ubuntu 12.04 x64, fog v 0.32, kernel 3.x or kitchensink based on linux kernel 3.6)