As I told someone recently, if you already have a linux install with a working grub install then don't bother to install grub at all. Just boot back into the first install and update grub. Done. That is the safest and least messy way of handling it. Doing it this way keeps grub from duplicating the entries over and over also. The person had thought to get fancy and install grub to the partition to keep from messing up his main install and boot menu in case he decided he wanted to stick with his first install and wipe the second one. Needless to say he ended up at a grub prompt and no clue how to fix anything.
Even better, make your first partition a small partition that does nothing but holds the grub config files. Then it is completely separated from any install. No need to bother installing grub ever again.
I recently went back to my old way of doing it (since I have been playing with other distros) and that is similar to the above. I have the grub config files on sda1 which is where I keep my data already. This is how I use to do it with the old grub as well.
So I still can't really see a point to installing grub to a partition.
Now for my next question...
If an installer was just going to install grub without confusing the user would hd0 be a safe default? I wonder if hd0 is correctly interpreted to be the device that the bios recognizes as the proper bootable drive? What is a safe and foolproof method...is there one? I need to dig a box out of the closet with multiple hard drives and play with it I guess....probably wont though...
I also though that maybe running os-prober and if any linux is detected then just mount that partition and update grub. Not sure it is nice to do that without informing the user first though.
I also posted a couple grub install scripts at
my forum....
I use one to reinstall grub from a live image and the other when I just want to move grub around. Not that useful but info nevertheless...