To usage Radeon under AOS 4.1 with Voodoo card in PCi slot (Mediator), you can lock pin A26 (Init Device Select).
Pinout PCi here: http://pinouts.ru/Slots/PCI_pinout.shtml
I made simple switch
I found source of problem and solution.
Problem is new kernel in kicstart drawer.
I exchanged it on old kernel and everything is OK (no frezze when usage 3d on RADEON, Early Startup Menu works fine on Radeon, driver Voodoo works).