> The Debian 8 nouveau drivers do not work correctly with G5 machines.
> If you attempt to install a desktop environment while in the
> installer, you will be met with a garbled screen, and constant
> nouveau errors. More info here:
>
> http://powerpcliberation.blogspot.com/2015/10/g5-and-g4-nouveau-
> modesetting-bug-and.html
>
>
> https://powerpcliberation.blogspot.com/2016/02/g5-nouveau-3d-acceleration.html
>
> As a fallback, you may apply this fix for PowerPC G5 machines only.
> Download the 'linux-image-4.10.8-powerpc64_1_powerpc.deb' on another
> computer:
>
> https://drive.google.com/drive/folders/0B8pqd5Ots1vfZXh6dzdXSnBSWmc
>
> ... and transfer it to a USB drive.
>
> In the Debian 8 system you installed without a desktop environment,
> plug your USB drive in, and input 'sudo mount /dev/sdx1 /mnt'
> ('sdb1' if you have one HD, 'sdc1' if you have two HDs), and then
> 'cd /mnt'. Once you're in the same directory as the linux-image.deb
> on your USB drive, run 'sudo dpkg -i *.deb'. And once it's in, do
> 'sudo nano /etc/yaboot.conf', and make sure these configurations are
> replicated in your copy:
>
> image=/boot/vmlinux-4.10.8-powerpc64
>  label=Linux
>  read-only
>  initrd=/boot/initrd.img-4.10.8-powerpc64
>
> Ctrl + X ---> Y ---> Return, and then enter 'sudo ybin'. Then,
> reboot. You should now be free to install a desktop environment +
> LightDM without crashing.
>
> ~ [The PowerPC Debian Wiki (Fixes, Debian 8)][1]

A custom-compiled release of Linux 4.10.8 (dated April 2, 2017)
specifically tailored for PowerPC G5-based machines with nVIDIA GPUs
running any version of Debian 8 Jessie, in order to fix a serious
display issue in the Nouveau graphics driver.

Uploaded here to provide a level of redundancy should the source
Google Drive repository go offline / become inaccessible.

Compatibility
Architecture: PPC

All PowerPC G5-based Macs using nVIDIA graphics running Debian 8
Jessie

  [1]: https://forums.macrumors.com/threads/the-powerpc-debian-wiki.2178457/