Remove GRUB from partition (not mbr)

[ercoppa]

Hi, I have two GRUB installed (some tests :P) on my disk:
- /dev/sda3
- /dev/sda4

Grub was installed in this way (e.g. /dev/sda3):

root (hd0,2)
setup (hd0,2)

So, GRUB is not installed in disk's MBR.

I want only one GRUB (Refit now shows me two tux), how can I uninstall the second GRUB from /dev/sda4?

Greets, ercoppa