Following the entry a single Grub for all your Linux of the wonderful blog of FORAT, which explains how to create entries by hand in GRUB when you install multiple operating systems and you want to keep the original GRUB, I will let me for once disagree with him and put my way of doing this by writing here, I think it is a little easier and so I’ll give the example of Windows XP. When you have installed Linux and XP on the same machine, what we have in the MBR is the Manager of GRUB bootloader, and within this a title such as for example XP input. If edit that entry (by pressing e) from GRUB, we see these lines: root (hd0, 0) chainloader + 1 makeactive these lines what they do is pass control to the Manager the XP boot, which rather than being in the MBR is partition 1, hence the (hd0, 0). Therefore can do same for linux. Does put us in a typical scenario: 1? partition hda1 > Windows XP (with your bootloader partition hda1 2? partition) makeactive chainloader + 1 then just below enters it for Windows XP create a new for our Debian: title Debian Lenny root (hd0, 2) chainloader + 1 makeactive save, and restart and load GRUB from the MBR that of Ubuntu, will leave us three innings Ubuntu Windows XP Debian Lenny if pressed Debian Lenny does is charging us the hda3 partition Debian GRUBClick in the kernel by default and ready.
I see you 2 advantages to this method: you can install several operating systems, having the GRUB that we like in the MBR, and through this charge the GRUB of other operating systems. We don’t have to worry about updates. If you exit a new debian kernel and updates the GRUB does not pass anything, it does us well. The other way, we would have to return to editing the menu.lst with the new kernel. Although everything is of course improvable.
I accept suggestions and criticisms.