diff --git a/Utils.h b/Utils.h
index a7dda7a..54b8dd8 100644
--- a/Utils.h
+++ b/Utils.h
@@ -57,7 +57,7 @@
  * ONLY for use with app-specific data directories on external storage!
  * (eg, /Android/data/com.foo, /Android/obb/com.foo, etc.)
  */
-int PrepareAppDirFromRoot(std::string path, int appUid);
+int PrepareAppDirFromRoot(const std::string& path, const std::string& root, int appUid);
 
 /* fs_prepare_dir wrapper that creates with SELinux context */
 status_t PrepareDir(const std::string& path, mode_t mode, uid_t uid, gid_t gid);