@Jim

The ROMs for the R200 variants are mostly identical. You can tell they all use the same code base, and in some cases, only integer constants (default register values) have changed. If the 8500 uses a single aperture to access all 128 MiB of RAM, fixing it might be as simple as changing one or two constant values in the FCode image.

EDIT: AMD seems to be open to sharing R2xx information if you ask directed questions; they've provided everything short of the original documentation. I'm hoping a kind soul from their GPU team can fill in a few of the blanks for me with respect to initializing the R2xx memory controller.

[ Edited by Trev on 2010/11/22 13:44 ]