Has anyone managed to get the atyfb driver working happily on a Bondi
iMac at any bit depth other than 8bpp?

The system works merrily at 1024x768x8bpp but I need to get the
framebuffer device operating at least at 16bpp (800x600 resolution
would be fine).

(If you've achieved this feat, could you send your fb.modes to me?)

Thanks for any help people can provide - I've spent ages googling,
experimenting with different kernel modelines, ... - I can't at this
point even determine if the correct syntax for cmode is to use 0
(8bpp), 1 (16bpp), 2 (24bpp) per the macmodes.h file, or whether the
right thing to do is use the actual desired video mode.