diff --git a/BuildLiveCD b/BuildLiveCD
index d1412bb0..f451b96e 100755
--- a/BuildLiveCD
+++ b/BuildLiveCD
@@ -32,11 +32,12 @@ SUITES=""
 PROPOSED=""
 IMAGEFORMAT=""
 
-while getopts :s:d:f:p name; do case $name in
+while getopts :s:d:f:p:a name; do case $name in
     s)	SUBARCH="$OPTARG";;
     d)	NEWSUITE="$OPTARG";;
     f)	IMAGEFORMAT="-f$OPTARG";;
     p)	PROPOSED="-p";;
+    a)	APT_SOURCE="$OPTARG";;
 esac; done;
 shift $((OPTIND-1))
 
@@ -103,6 +104,23 @@ set -e
 
 for STE in $SUITES; do
     if [ -d ~/build-${STE}-live/chroot-${STE} ]; then
+	if [ -n "$APT_SOURCE" ]; then
+	    sudo sed -i -e"\$a\
+deb $APT_SOURCE $STE main" ~/build-${STE}-live/chroot-${STE}/etc/apt/sources.list
+	    # allow unsigned sources, unfortunately
+	    echo 'APT::Get::AllowUnauthenticated "yes";' | sudo tee ~/build-${STE}-live/chroot-${STE}/etc/apt/apt.conf.d/extra-source-allows-unauthenticated-sources > /dev/null
+	    # and add the preferences rules :(
+	    APT_PIN=$(echo $APT_SOURCE | sed -e's,http://,,; s,/.*,,')
+	    cat | sudo tee ~/build-${STE}-live/chroot-${STE}/etc/apt/preferences.d/local-source-preferred-even-downgrade > /dev/null <<EOF
+Package: *
+Pin: release a=$STE
+Pin-Priority: 500
+
+Package: *
+Pin: origin $APT_PIN
+Pin-Priority: 1001
+EOF
+	fi
 	sudo chroot ~/build-${STE}-live/chroot-${STE} apt-get -qq update || true
 	sudo chroot ~/build-${STE}-live/chroot-${STE} apt-get -y dist-upgrade || true
     fi
@@ -164,3 +182,10 @@ for STE in $SUITES; do
 	fi
     done
 done
+for STE in $SUITES; do
+    if [ -d ~/build-${STE}-live/chroot-${STE} ] && [ -n "$APT_SOURCE" ]; then
+	sudo sed -i -e"/$APT_SOURCE $STE/d" ~/build-${STE}-live/chroot-${STE}/etc/apt/sources.list
+	sudo rm -f ~/build-${STE}-live/chroot-${STE}/etc/apt/apt.conf.d/extra-source-allows-unauthenticated-sources
+	sudo rm -f ~/build-${STE}-live/chroot-${STE}/etc/apt/preferences.d/local-source-preferred-even-downgrade
+    fi
+done
diff --git a/debian/changelog b/debian/changelog
index defc4387..3a7d3624 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -1,3 +1,10 @@
+livecd-rootfs (1.133ubuntu1) UNRELEASED; urgency=low
+
+  * Add -a option to BuildLiveCD to allow pulling from an additional apt
+    source.
+
+ -- Steve Langasek <steve.langasek@ubuntu.com>  Tue, 20 Jul 2010 18:15:22 +0200
+
 livecd-rootfs (1.133) maverick; urgency=low
 
   * adjust BuildLiveCD PUBDIR variable to match reality (uses SUBARCH on the