Code
echo "nvidia" > /storage/modprobe.d/blacklist.conf
cp /etc/X11/xorg-radeon.conf /storage/.config/xorg.conf
cp /usr/lib/udev/rules.d/97-xorg.rules /storage/.config/udev.rules.d/97-xorg.rules
^ You can edit the 97-xorg.rules files so there is only a line for the "radeon" driver. I'm not sure this will achieve anything though as if I read the scripts correctly it''s simply not finding the radeon card hardware, which maybe points towards slow loading drivers and some kind of timing issue.