-What about a flashed ATi X1900GT? I'm getting a white screen on MOS in my G5 (11,2)... Works fine with OSX Tiger & Sorbet Leopard.
https://forums.macrumors.com/threads/radeon-x1900-g5-mac-edition-cheap-n-easy-flashing-guide.2308103/
Amiga A500
-Classic 520 '020
-32GB CF, 8MB, 1MB Chip mod
-Amiga OS 3.2.1
PowerMac 5G DC 2.3Ghz (11,2)
-12GB Ram/240GB SSD
-Tiger 10.4.11 w/ OS9 Classic environment
-Sorbet Leopard 10.5.9
-Flashed ATi X1900 not MorphOS compatible