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Re: BootX documentation

On 4/16/21 2:47 PM, David VANTYGHEM wrote:
> Perhaps any interesting things in this file ?
> https://opensource.apple.com/source/bless/bless-37/README.BOOTING

It does answer some questions, namely about blessing, the tbxi attribute and
the number of backslahes in the OpenFirmware path to be set as boot-device


> New World machines (with OF 3.0+) support HFS+, ISO9660, and FAT. When
> Mac OS X is installed on an HFS+ volume, BootX is typically placed
> in the /System/Library/CoreServices directory, and given the HFS+
> type attribute of 'tbxi'. Furthermore, the CoreServices folder is
> "blessed", which means that it's directory ID (analogous to an inum
> in FFS terminology) is recorded, in the HFS+ volume header.

So, it may or may not be necessary to add the tbxi attribute, depending
on whether one wants to be able to boot the bootloader using the "tbxi"

> The next two components of
> boot-device are used to located the BootX secondary loader. The first
> ("\\") is a special syntax denoting the blessed system folder
> mentioned above. 

So, what grub-install does here is actually correct, i.e. setting the
path to &device;:&partition;,\\BootX, as "\\" sets the search path to
the blessed folder.

And further:

> Because a
> directory (and not a file) was specified, ":tbxi" is used to filter
> entries that have the HFS+ type of 'tbxi'. If multiple files in the
> directory have the same HFS+ type, the first one (in directory order)
> is used, which is somewhat non-deterministic from the operating system
> point of view, and is not necessarily the alphabetically first entry.


> Also, we could
> have avoided the filter mechanism and specified the path to BootX
> directly. The following forms are all equivalent, and would occur
> after the last comma in boot-device variable (assuming the path itself
> doesn't have commas itself):
> \\:tbxi
> \\BootX
> \System\Library\CoreServices\:tbxi
> \System\Library\CoreServices\BootX

So, the bootloader installed that way with grub-install should actually
work. My only guess - and that needs to be verified - is that the path
set in OpenFirmware is not correct.

On the other hand, I wonder whether the "tbxi" attribute is actually
necessary for a boot entry to show up in the <<Option>> key menu which
is what we actually want.


 .''`.  John Paul Adrian Glaubitz
: :' :  Debian Developer - glaubitz@debian.org
`. `'   Freie Universitaet Berlin - glaubitz@physik.fu-berlin.de
  `-    GPG: 62FF 8A75 84E0 2956 9546  0006 7426 3B37 F5B5 F913

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