diff --git a/cores/esp8266/FS.cpp b/cores/esp8266/FS.cpp
index 55bae8f5c5..8241083ab0 100644
--- a/cores/esp8266/FS.cpp
+++ b/cores/esp8266/FS.cpp
@@ -196,6 +196,7 @@ File FS::open(const char* path, const char* mode) {
         DEBUGV("FS::open: invalid mode `%s`\r\n", mode);
         return File();
     }
+    if (strlen(path) > 31) return File(); 
 
     return File(_impl->open(path, om, am));
 }