I'm running Linux Mint 14 and Lubuntu 12.10 on my laptop. After updating Grub on Mint it automatically detected Lubuntu and I have no problem booting into it. But I have no clue, how to set specific kernel options for Lubuntu.
Editing "GRUB_CMDLINE_LINUX_DEFAULT" in /etc/default/grub only affects Mint and not Lubuntu. Also editing /etc/default/grub on the Lubuntu partition didn't changed its boot options (so update-grub on Mint doesn't adept the boot options for Lubuntu set there). Neither changes editing "GRUB_CMDLINE_LINUX" anything. I tried ddg-ing and googling for help, but did not find anything remotely useful.
In short:
I want to set specific boot parameters for Lubuntu while using Grub2 installed on a Mint partition. How do I do that?
Edit:
Sorry for bothering, I eventually figured it out myself. Basically the Grub-Loader adepts the settings of the /boot/grub/grub.cfg file, not of the files generating the grub.cfg.
How to set boot options for a secondary partition:
1. Boot into said partition
2. Configure the Grub of this partition using /etc/default/grub or the files in /etc/grub.d/
3. run update-grub on the secondary OS (the step I forgot)
4. restart and boot into the main partition (the one Grub is installed on)
5. run update-grub there
6. restart, enjoy.

