Fix two typos
diff --git a/make_image.sh b/make_image.sh
index 81dd97c..0d5074b 100755
--- a/make_image.sh
+++ b/make_image.sh
@@ -144,7 +144,7 @@
 if [ -n "$IMAGEONLY" ]; then
     # Build image from chroot
     sudo vmbuilder $HYPER ubuntu $ARGS \
-      --existing-chroot=$CHR \
+      --existing-chroot=$CHROOTDIR \
       --overwrite \
       --rootsize=$ROOTSIZE \
       --swapsize=$SWAPSIZE \