diff --git a/README.md b/README.md
index 769cd66..930180f 100644
--- a/README.md
+++ b/README.md
@@ -25,7 +25,7 @@ imports = [
 ## Auto upgrade
 Adds a few new options to ``system.autoUpgrade``
 
-``updateFlake`` pulls in new changes from git repo of your flake and updates the lock file.
+``updateFlake`` pulls in new changes from git repo of your flake and updates the lock file. Make sure your flake parameter is a directory not a flake url, otherwise it wont work.
 
 ``failureNotification`` sends a notification to a ntfy topic on an auto upgrade failure