am d4208f9f: remove the notion of "root path"; support mixed flash types (do not merge)

Merge commit 'd4208f9f9d4e9f268ba1888c1fe879ee73eb7e47' into gingerbread-plus-aosp

* commit 'd4208f9f9d4e9f268ba1888c1fe879ee73eb7e47':
  remove the notion of "root path"; support mixed flash types (do not merge)