diff --git a/build.sh b/build.sh
index a1a6666..2b08c3e 100755
--- a/build.sh
+++ b/build.sh
@@ -22,7 +22,7 @@ STAMP=$(date +%F)
 
 cat > Dockerfile <<EOF
 FROM scratch
-ADD rootfs.tar.gz /
+ADD $ROOTFS.tar.gz /
 CMD ["bash"]
 EOF