- deb http://backports.debian.org/debian-backports squeeze-backports main
- deb-src http://backports.debian.org/debian-backports squeeze-backports main
+ deb http://backports.debian.org/debian-backports squeeze-backports main contrib non-free
+ deb-src http://backports.debian.org/debian-backports squeeze-backports main contrib non-free