Support for DOT3 bumpmapping is horribly broken in the Unichrome driver.  First
of all, both EXT_texture_env_combine_dot3 and ARB_texture_env_combine_dot3 are
advertised, but there is only any support for the ARB version.  I believe that
the implementor assumed that the enums and the behavior for both were the same.
 Bad assumption! :)

Not only that, the code that handles GL_COMBINE only has support for GL_DOT3_RGB
and GL_DOT3_RGBA for the second texture unit.  There's no code to handle those
combine modes for the first texture unit!