diff --git a/preseed/finish.sh b/preseed/finish.sh
index 2bb84ce..7b5bc79 100755
--- a/preseed/finish.sh
+++ b/preseed/finish.sh
@@ -1,25 +1,30 @@
 #!/bin/bash
 
 set -e
 
 PUPPET_MASTER=pergamon
 PUPPET_MASTER_FQDN="$PUPPET_MASTER.internal.softwareheritage.org"
 LOCATION=sesi_rocquencourt
 
+cat > /etc/apt/sources.list.d/backports.list <<EOF
+deb https://deb.debian.org/debian stretch-backports main
+EOF
+
 apt-get update
 
+apt-get -y -o Dpkg::Options::="--force-confdef" -o Dpkg::Options::="--force-confold" install -t stretch-backports facter
 apt-get -o Dpkg::Options::="--force-confdef" -o Dpkg::Options::="--force-confold" -y dist-upgrade
 
 systemctl disable puppet.service
 
 mkdir -p /etc/facter/facts.d
 echo "location=$LOCATION" > /etc/facter/facts.d/location.txt
 
 echo "192.168.100.29 $PUPPET_MASTER_FQDN $PUPPET_MASTER" >> /etc/hosts
 
 # first time around, this will:
 # - update the node's puppet agent configuration defining the puppet master
 # - generate the certificates with the appropriate fqdn
 # - unfortunately, for now, this fails though, when not being able to
 #   install the apt-transport-https package
 puppet agent --server $PUPPET_MASTER_FQDN --waitforcert 60 --test