I'm using Arnold core 22.214.171.124, C4DtoA 2.1.2, and the method to color hair was different in older versions of the plugin.
I've added an Arnold Parameters tag to my Hair object with 'Export UVs' checked. In the Hair object, I plugged in the geometry's UV tag to the UV parameter in the 'Advanced' tab. But the hair still renders black when I plugin an image texture to Base color or diffuse color of the 'standard_hair' shader.
Am I missing a step? Could you please outline the steps to generate hair, colored based on the texture of a given object?