The EtD should only be flashed for DMX if you are using it to produce DMX directly, I.e. connecting an express to the EtD output. In this configuration, each pair will have 1 DMX Universe on it. You can then use the combiner board as a splitter or make a custom cable to use the other three universes. When flashed this way, the EtD is not compatible with the pixel net hubs or the ssc and cannot be used to drive smart strings.
The active hub has a pic to convert pixel net to DMX so that you don't need another dongle for the DMX equipment, you can just mirror part of the pixel net universe for those devices...
RM