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)