Index: update.php
===================================================================
RCS file: /cvs/drupal/drupal/update.php,v
retrieving revision 1.323
diff -u -p -r1.323 update.php
--- update.php	18 May 2010 18:11:12 -0000	1.323
+++ update.php	26 Sep 2010 19:21:56 -0000
@@ -380,9 +380,6 @@ include_once DRUPAL_ROOT . '/includes/un
 
 update_fix_d7_requirements();
 
-// Now proceed with a full bootstrap.
-
-drupal_bootstrap(DRUPAL_BOOTSTRAP_FULL);
 drupal_maintenance_theme();
 
 // Turn error reporting back on. From now on, only fatal errors (which are
Index: includes/update.inc
===================================================================
RCS file: /cvs/drupal/drupal/includes/update.inc,v
retrieving revision 1.69
diff -u -p -r1.69 update.inc
--- includes/update.inc	25 Sep 2010 18:10:53 -0000	1.69
+++ includes/update.inc	26 Sep 2010 19:27:19 -0000
@@ -782,6 +782,11 @@ function update_parse_db_url($db_url, $d
  * @see update_resolve_dependencies()
  */
 function update_do_one($module, $number, $dependency_map, &$context) {
+  // Enforce cut down module list and reset module_implements().
+  $module_list[$module]['filename'] = drupal_get_filename('module', $module);
+  module_list(TRUE, FALSE, FALSE, $module_list);
+  module_implements('', FALSE, TRUE);
+
   $function = $module . '_update_' . $number;
 
   // If this update was aborted in a previous step, or has a dependency that