Maybe if we all email bitmain asking for an Rpi image for the U3 that works they would post one (and for anyone not planning to use an Rpi we could always deconstruct it if we know the cg version used).
I have tried everything I could think of using the settings designed for the new chip. I am now going through options settings for the old ones to see if any work (i.e. icarus options with amu setting etc.)
 So far no luck with anything.