> It turns out that the interface 9pi used for querying framebuffer depth
> is also now broken.  Setting framebuffer_depth=N in config.txt used to
> work for changing the pixel format, now it doesn't.

OK, new 9pi and 9pi2 kernels in /n/sources/contrib/miller should now do
the right thing for 24bpp, which can be requested with framebuffer_depth=24
in config.txt or vgasize=WxHx24 in cmdline.txt