diff --git a/includes/module.inc b/includes/module.inc
--- a/includes/module.inc
+++ b/includes/module.inc
@@ -694,6 +694,35 @@ function module_hook($module, $hook) {
 function module_implements($hook, $sort = FALSE, $reset = FALSE) {
   // Use the advanced drupal_static() pattern, since this is called very often.
   static $drupal_static_fast;
+  static $full_bootstrap;
+
+  // This ensures that this clause is only called once after full bootstrap has
+  // happened.
+  if (!isset($full_bootstrap) || $full_bootstrap == FALSE) {
+    $full_bootstrap = drupal_bootstrap(NULL, FALSE) == DRUPAL_BOOTSTRAP_FULL;
+
+    // In case we are pre-bootstrap, ensure to use a different static
+    // implementation.
+    if (!$full_bootstrap) {
+      if (!isset($drupal_static_fast)) {
+        // This does not need a drupal_static().
+        $drupal_static_fast['implementations'] = array();
+      }
+    }
+    elseif (isset($drupal_static_fast)) {
+      // The first time we come here after full bootstrap, but with
+      // $drupal_static_fast already populated, we reset the
+      // $drupal_static_fast variable.
+      // This MUST not use unset() as unset only resets
+      // the variable for the rest of the function, but
+      // restores it again for the next request.
+      $drupal_static_fast = NULL;
+
+      // And clear any existing drupal_alter() cache.
+      drupal_static_reset('drupal_alter');
+    }
+  }
+
   if (!isset($drupal_static_fast)) {
     $drupal_static_fast['implementations'] = &drupal_static(__FUNCTION__);
   }
@@ -726,6 +755,12 @@ function module_implements($hook, $sort = FALSE, $reset = FALSE) {
     }
     else {
       $implementations = $implementations->data;
+      // In case we don't have full bootstrap, yet, store the data also
+      // in the future static as that cache_get is always the full cache.
+      if (!$full_bootstrap) {
+        $module_implements_cache = &drupal_static('module_implements');
+        $module_implements_cache['implementations'] = $implementations;
+      }
     }
   }