Tambah berikut di dalam /etc/apt/sources.list
[code=’plain’]## debian mozilla
deb http://mozilla.debian.net/ squeeze-backports iceweasel-4.0[/code]
Kemaskini senarai pakej
aptitude install debian-keyring
GET http://mozilla.debian.net/archive.asc | gpg --import
gpg --export -a 06C4AE2A | sudo apt-key add -
aptitude update
Pasang Iceweasel 4.0
aptitude install -t squeeze-backports iceweasel