Ok, I've read a few posts about that, but either the people who wrote had a dual-boot Windows/Ubuntu, or I didn't understand the solution in the end... Anyway I'm just too scared of doing something wrong at this level, so here is the situation:
What happened
I had an iMac with rEFIt installed and a dual boot with Ubuntu 12.04. I went on Mac, and decided to free some space for Ubuntu, so I just shrunk the Mac partition cutting off 30Gb at the end (free space), that's ALL, and all was well. At least that's what I thought..
What's the current situation
Now I can still boot on Mac, but when I try to boot on Ubuntu I get a error: unknown filesystem
with the grub rescue>
prompt. I followed what I read on the forum to boot on Ubuntu:
set root=(hd0,3)
set prefix=(hd0,3)/boot/grub
insmod normal
normal
and this works well, but it's not a long term solution. I heard about BootRepair, but I'm on Mac, and from what I've seen, all the options of this software are for MBR, not EFI...
My opinion
From what I understand I need to tell EFI where to "redirect the bootloader" when I select the linux option in the rEFIt menu. Can't I do that from OSx directly? Or is it just grub that's messed up? If I have to use a liveUSB, please explain me what to do as if I was dumb, I really don't want to mess things up more... :S
insmod
option in theload_video
function ingrub.cfg
. Meanwhile, this broke the former linux badge in rEFIt, which now leads to a black screen with a blinking prompt, and no grub rescue anymore.