Update Debian Ports installation images 2021-04-14

[John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>]

Hi!

Here are the first test images where the installation of GRUB on PowerMacs
should finally work properly [1]. It took me quite some time and effort with
lots of testing to get the implementation right.

During the partitioning phase, the installer will pop up an empty question
dialog. Just answer that dialog with "<NO>" to continue. After that, the
installation should complete normally.

The installer now also correctly installs a boot script with an icon that
should show up in the OpenFirmware boot menu that can be invoked with the
<Option> key after the machine has been powered on.

Let me know how the image works for you, then I can commit the changes for
the grub-installer package to git when we know it works for most people for
the time being.

If it doesn't work, remember I need the installation log located in /var/log
as the file "syslog".

Thanks,
Adrian

> [1] https://cdimage.debian.org/cdimage/ports/snapshots/2021-04-14/

-- 
 .''`.  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