This is an interesting thread - it make sme wonder how the original Bose head unit was able to do fading. Did it have a separate control wire or were there simply phasing properties in the audio signal that tell the amp to use the rear vs the front? Does the Bose amp simply split the signal between front and back meaning that signal-wise (not counting amplitude):
Right-Front = Right-Rear
Left-Front = Left-Rear

If this isn't the case, then what would control the signal difference between front and back.

I'd be curious to know if you found that your rear speakers worked again when you reverted back to version 1.0.