diff --git a/debian/changelog b/debian/changelog
index 820ed91b..75f77e35 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -1,8 +1,13 @@
 livecd-rootfs (2.459) UNRELEASED; urgency=medium
 
+  [ Steve Langasek ]
   * Remove spurious call to 'sync'; we don't need to flush all disk caches
     on the system to cleanly unmount a partition.
 
+  [ Gary Wang ]
+  * Add GENERATE_ROOTFS_ONLY to support generating a single rootfs.
+  * Add a test for SUBPROJECT when PROJECT comes to ubuntu-server.
+
  -- Steve Langasek <steve.langasek@ubuntu.com>  Tue, 19 Sep 2017 13:15:33 -0700
 
 livecd-rootfs (2.458) artful; urgency=medium
diff --git a/live-build/auto/build b/live-build/auto/build
index 5c7b88ce..35de4f81 100755
--- a/live-build/auto/build
+++ b/live-build/auto/build
@@ -229,10 +229,16 @@ EOF
 	(cd chroot && find usr/share/doc -maxdepth 1 -type d | xargs du -s | sort -nr)
 	echo END docdirs
 
-	lb binary "$@"
-	touch binary.success
+	if [ -z "${GENERATE_ROOTFS_ONLY:-}" ]; then
+		lb binary "$@"
+		touch binary.success    
+	fi
 ) 2>&1 | tee binary.log
 
+if [ ! -z "${GENERATE_ROOTFS_ONLY:-}" ] && [ "${GENERATE_ROOTFS_ONLY}" = 1 ]; then
+	exit 0
+fi
+
 # bash has trouble with the build.sh sourcing arrangement at the top of this
 # file, so we use this cheap-and-cheerful approach rather than the more
 # correct 'set -o pipefail'.
diff --git a/live-build/auto/config b/live-build/auto/config
index 3f504463..f8515239 100755
--- a/live-build/auto/config
+++ b/live-build/auto/config
@@ -757,7 +757,7 @@ EOF
 		;;
 esac
 
-if [ $PROJECT = ubuntu-server ] && [ $SUBPROJECT != live ]; then
+if [ $PROJECT = ubuntu-server ] && [ ! -z "${SUBPROJECT:-}" ] && [ $SUBPROJECT != live ]; then
 	cat > config/hooks/100-remove-fstab.chroot <<EOF
 #! /bin/sh
 rm -f /etc/fstab