Re: Why it's so difficult to fix PowerMac booting for good
Hello!
On Wed, 2023-05-10 at 10:24 +0200, John Paul Adrian Glaubitz wrote:
> Installing a bootloader on a PowerMac requires an HFS or HFS+ partition where
> the initial bootloader must be copied and "blessed" such that the firmware of
> a PowerMac finds and loads the bootloader. The detailed process is explained
> here [1], for example. In debian-installer, this process is performed by the
> grub-installer script [2].
I made some experiments with GRUB on Apple PowerMac to obtain some more data points
on the boot process. I tested both HFS and HFS+ as well as other filesystems and
I also used GRUBs own bless tool.
Here's what I found out:
GRUB's grub-macbless does not work at all. Neither is it sufficient to bless the
System/Library/CoreServices folder with just grub-macbless to get a bootable
system nor does it help combining it with
"hattrib -c UNIX -t tbxi :System:Library:CoreServices:BootX"
Only the combination of both
"hattrib -c UNIX -t tbxi :System:Library:CoreServices:BootX"
"hattrib -b System:Library:CoreServices"
makes the system boot.
==================================================================================
For this reason, I couldn't test HFS+ since hfsutils from where hattrib comes from
does not support HFS+.
Also, I ran into a strange problem with HFS+ where I couldn't list the files in a
mounted HFS+ filesystem. I got the error "Value too large for defined data type"
in this case. This could be worked around after creating an empty file in the root
of the HFS+ filesystem using
"touch /path/to/hfs/plus/folder".
==================================================================================
Installing on a FAT filesystem does not work at all. grub-install actually refuses
the installation if the target directory for --macppc-directory is not an HFS/HFS+
filesystem.
==================================================================================
To conclude, there is currently no better way in getting an Apple PowerMac to boot.
Also, I have reached to Apple Legal and asked them to change the license for the
»hfs« [1] package to a more permissive license which is compatible with Debian's
DFSG.
Adrian
> [1] https://github.com/apple-opensource/hfs
--
.''`. John Paul Adrian Glaubitz
: :' : Debian Developer
`. `' Physicist
`- GPG: 62FF 8A75 84E0 2956 9546 0006 7426 3B37 F5B5 F913
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