diff --git a/install.sh b/install.sh
index 0a06273..8269d11 100755
--- a/install.sh
+++ b/install.sh
@@ -31,10 +31,9 @@ function bootstrap {
 ## MAIN
 
 [[ "$UID" -ne 0 ]] && echo 'root privilege required' && exit 1
-
 if [[ -v MIAOU_BASH_DIR ]]; then
+  miaou-bash "$MIAOU_BASH_DIR/lib/self-upgrade.bash"
+else
   bootstrap
   miaou-bash "$MIAOU_BASH_DIR/lib/init.bash"
-else
-  miaou-bash "$MIAOU_BASH_DIR/lib/self-upgrade.bash"
 fi