Bug#427492: grub-efi: bless equivalent for Linux

[Stefan Monnier]

>> Oh and in upstream there's a patch for a bless command for grub2, which
>> modifies the HFS+ somehow like bless --directory
> I guess that's the PowerPC bless command. TTBOMK the bless command for
> Intel machines only sets EFI variables.

No: the `bless' command on Intel Macs can do 2 different things,
depending on the arguments passed to it.  It can either "bless" a folder
on an HFS+ partition (this only changes the filesystem metadata on-disk
and nothing else), or it can change some firmware variables to set which
device to boot from by default at the next boot.

Note that Apple's firmware is fairly "clever", so if the default boot
device can't be found, it will look for other bootable devices (first
by searching for HFS+ partitions with a blessed folder, then by trying
to boot from a CD, or else falling back on booting via the legacy BIOS
code).

Macs are able to load an EFI boot-loader from FAT and HFS+ (and there's
even a rumor it can load one from ext2, tho I haven't checked it), but
since only HFS+ supports the notion of a "blessed" folder, if you want
to boot from an non-HFS+ device (e.g. the EFI-system partition), you'll
need to set the firmware variables.  OTOH if you use an HFS+ partition,
you can often get away without fiddling with the firmware boot variables.

I strongly support the inclusion of hfspbless in Debian.  Maybe as part
of grub-efi, or hfsprogs.


        Stefan