sudo aptitude reinstall libffi6
The following packages will be REINSTALLED:
  libffi6 
0 packages upgraded, 0 newly installed, 1 reinstalled, 0 to remove and 0 not upgraded.
Need to get 0 B of archives. After unpacking 0 B will be used.
E: I wasn't able to locate a file for the libffi6 package. This might mean you need to manually fix this package.
E: I wasn't able to locate a file for the libffi6 package. This might mean you need to manually fix this package.
E: Internal error: couldn't generate list of packages to download