diff --git a/install-dev/upgrade/php/drop_image_type_non_unique_index.php b/install-dev/upgrade/php/drop_image_type_non_unique_index.php
index ad6e0ec4b..b686e5124 100644
--- a/install-dev/upgrade/php/drop_image_type_non_unique_index.php
+++ b/install-dev/upgrade/php/drop_image_type_non_unique_index.php
@@ -27,8 +27,7 @@
 
 function drop_image_type_non_unique_index()
 {
-	$index = Db::getInstance()->executeS('SHOW index FROM `'._DB_PREFIX_.'image_type` where column_name = "name" and non_unique=1');
-	// do not use pSql, this function is not defined
-	Db::getInstance()->execute('ALTER TABLE `'._DB_PREFIX_.'image_type` DROP INDEX "'.$index.'"');
+	$index = Db::getInstance()->getValue('SHOW index FROM `'._DB_PREFIX_.'image_type` where column_name = "name" and non_unique=1');
+	Db::getInstance()->execute('ALTER TABLE `'._DB_PREFIX_.'image_type` DROP INDEX "'.pSQL($index).'"');
 }