diff --git a/cores/oak/FS.h b/cores/oak/FS.h
index 07b58c0..07cd814 100644
--- a/cores/oak/FS.h
+++ b/cores/oak/FS.h
@@ -124,7 +124,7 @@ class FS
 };
 
 } // namespace fs
-
+#ifndef FS_NO_GLOBALS
 using fs::FS;
 using fs::File;
 using fs::Dir;
@@ -133,7 +133,10 @@ using fs::SeekSet;
 using fs::SeekCur;
 using fs::SeekEnd;
 using fs::FSInfo;
+#endif //FS_NO_GLOBALS
 
-extern FS SPIFFS;
+#if !defined(NO_GLOBAL_INSTANCES) && !defined(NO_GLOBAL_SPIFFS)
+extern fs::FS SPIFFS;
+#endif
 
 #endif //FS_H