diff --git a/boost.install b/boost.install
index 45af656880f6b9d1eb53c26cdf290856a8bf32d1..71ef887566fd77ea77c6808008a82b32fdc9a492 100644
--- a/boost.install
+++ b/boost.install
@@ -681,6 +681,8 @@ function boost_update_6108() {
  * Update 6109 - Change .js to .json
  */
 function boost_update_6109() {
+  // _boost_change_extension() is located in the module file, make sure thats loaded.
+  drupal_load('module', 'boost');
   variable_set('boost_json_extension', '.json');
   _boost_change_extension('.js', '.json');
   drupal_set_message(t('Be sure to update your htaccess rules.'), BOOST_CACHE_JSON ? 'warning' : 'status');