Re: macosx (darwin) fail to boot from Grub2

[Andrei Borzenkov <arvidjaar@gmail.com>]

В Sun, 28 Jun 2015 11:45:49 +0200
danjde@msw.it пишет:

> Hi friends,
> I've just installed successifully Ubuntu 14.04 on iMac 9.1 (Darwin).
> 
> The partitions are so suddivided:
> 
> 
> |-EFI-FAT32-|---MAC-HFS+---|--/BOOT-EXT4--|----/ROOT-EXT4----|----/HOME-REISERFS-----|---SWAP---|
> 
> 
> On sda is installed rEFIT.
> Grub2 is installed on sda3 (/BOOT)
> 
> Linux boot correctly from Grub2, MAC not (only from rEFIT). Booting 
> from Grub2 MAC, it does't found the system partition.
> 
> 
> Here the Grub2 (macosx) entry:
> 
> 
> menuentry 'Mac OS X (32 bit) (su /dev/sda2)' --class osx --class darwin 
> --class os $menuentry_id_option 'osprober-xnu-32-86296317cf88a9f9'  {

This does not work on native EFI grub (i.e. when grub platform is
x86_64-efi or i386-efi). You can use EFI chainloading to start Mac OS X
bootloader instead of trying to load kernel directly. Somehing like

To load OSX, use the following section in grub.cfg:

menuentry "MacOSX" {
  # Search the root device for Mac OS X's loader.
  search --file --no-floppy --set=root /usr/standalone/i386/boot.efi
  # chainload the loader, pass parameters like -v directly
  chainloader (${root})/usr/standalone/i386/boot.efi #-v
}

I think boot.efi is also present under some other path, I forgot. The
above is from Ubuntu page.