diff --git a/lib/jslib.php b/lib/jslib.php
index bbfb895e534..b763038406c 100644
--- a/lib/jslib.php
+++ b/lib/jslib.php
@@ -107,6 +107,11 @@ function js_minify($files) {
         return '';
     }
 
+    // We do not really want any 304 here!
+    // There does not seem to be any better way to prevent them here.
+    unset($_SERVER['HTTP_IF_NONE_MATCH']);
+    unset($_SERVER['HTTP_IF_MODIFIED_SINCE']);
+
     if (0 === stripos(PHP_OS, 'win')) {
         Minify::setDocRoot(); // IIS may need help
     }
@@ -132,7 +137,7 @@ function js_minify($files) {
     $error = 'unknown';
     try {
         $result = Minify::serve('Files', $options);
-        if ($result['success']) {
+        if ($result['success'] and $result['statusCode'] == 200) {
             return $result['content'];
         }
     } catch (Exception $e) {