Avoiding the use of `dd` (crashing command).

`python -m zipfile -e ARCHIVE TARGET` don't do the work every time :

Traceback (most recent call last):
  File "/usr/local/lib64/python2.7/runpy.py", line 162, in _run_module_as_main
    "__main__", fname, loader, pkg_name)
  File "/usr/local/lib64/python2.7/runpy.py", line 72, in _run_code
    exec code in run_globals
  File "/usr/local/lib64/python2.7/zipfile.py", line 1439, in <module>
    main()
  File "/usr/local/lib64/python2.7/zipfile.py", line 1414, in main
    with open(tgt, wb) as fp:
IOError: [Errno 21] Is a directory: 'TARGET/ARCHIVE/'