I have a SATA disc with several partitions, one with Centos and one with Clonezilla Live. Grub sees both entries correctly, and starts either OS correctly.
Then I install my big monster (a bit of sarcasm here) data hardware RAID (which bios and I'm assuming grub too, see as one HD), and pop! the grub does not load either OS. I disconnect the monster, and pop! it all works again.
The issue here, I think, is that grub does not map the (hd*) to either HD correctly. I don't know what order criteria there is within the grub HD detection, but it maps the monster RAID as hd0 instead of the usual SATA disc.
How do I influence the GRUB HD detection/mapping, so that grub will point the right hard drive, irrespective of whether the RAID drive is installed or not?
map (hd0) (hd1) does not solve the problem.