[xubuntu-users] grub2 autoupdate problem

[michele]

hi i'm michele from italy,i've a question: i need to lockdown the 
autoupdate of grub2 in ubuntu 9.10 ,i need that ubuntu write grub only 
in the partition and not in the mbr.
This is my disks layout:
ide0 opensolaris with his grub on the ide mbr (and i start ubuntu with  
chainloader +1)
sata0 xubuntu

every time i ugrade ubuntu,it writes its grub2 on mbr of ide0 and i 
can't boot opensolaris

any hints?