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I'm trying to triple-boot MacOS, Centos 6, and Ubuntu 12.04.

Here's my approach:

  • Use rEFIt to choose between MacOS and grub
  • Use grub to choose between CentOS and Ubuntu

I have all installed on my system, but only MacOS works. Right now, trying to go into grub from MacOS results in this error (verbatim, since I don't have copy+paste without an OS)

No operating system found

I suspect that I accidentally killed the boot partition somehow while installing CentOS, since Ubuntu worked before that.

So, I boot into a Ubuntu USB-based livecd, and run

# grub-install /dev/sda5 # sda5 is a boot partition
/usr/sbin/grub-probe: error: cannot find a device for /boot/grub (is /dev mounted?).

So what am I doing wrong?
P.S. Adding a way to boot straight into Ubuntu or CentOS from rEFIt would be fine too.

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