bmap-tools(https://github.com/01org/bmap-tools/tree/master/docs) is a set of generic tools for creating the block map (bmap) for a file, and copying files using the block map. The idea is that large file containing unused blocks, like raw system image files, can be copied or flashed a lot faster with bmaptool than with traditional tools like "dd" or "cp".

Adding support of bmaptool to wic would mean making wic images sparse and generating .bmap file using bmaptool API. If this is done images can be flashed much faster using bmapcopy utility.