Testers on PowerMac needed - overwriting the boot-device in NVRAM
Hello!
I would like to ask users running Debian on a real PowerMac machine (G3, G4, G5 etc)
to help me verify a theory on the boot mechanism. In particular, the question is
whether we can skip setting the boot-device in NVRAM in the grub-installer script
which causes incompatibilities with the PowerMac emulation in QEMU [1].
According to Apple's documentation [2], Open Firmware will automatically search for
available operating systems, so there is no need to explicitly set the path to
the boot device.
To verify this, I set the boot device on my iBook G4 to NULL and checked whether the
machine would still boot which turns out to be true. However, before I change the
code in grub-installer, I want to make sure it won't break any other PowerMacs.
So, if you would like to help, please try the following.
As root, run:
root@ibook-g4:~# nvram --print-config=boot-device
/pci@f4000000/ata-6@d/@0:2,\\:txbi
root@ibook-g4:~# nvram --update-config boot-device=""
root@ibook-g4:~# nvram --print-config=boot-device
root@ibook-g4:~# reboot
If your machine still comes up after changing "boot-device" to zero, we know that
it's safe to drop the NVRAM part from the grub-installer script for PowerMacs.
This will fix the remaining compatibility with QEMU.
Thanks,
Adrian
> [1] https://lists.debian.org/debian-powerpc/2022/03/msg00029.html
> [2] https://opensource.apple.com/source/bless/bless-37/README.BOOTING
--
.''`. 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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