diff --git a/module/install/model.php b/module/install/model.php
index 8ccc20e70c..f01e8c9b8f 100644
--- a/module/install/model.php
+++ b/module/install/model.php
@@ -370,6 +370,10 @@ class installModel extends model
             {
                 $table = str_replace('--', '', $table);
             }
+
+            /* Skip sql that is note. */
+            if(preg_match('/^--|^#|^\/\*/', $table)) continue;
+
             $table = str_replace('`zt_', $this->config->db->name . '.`zt_', $table);
             $table = str_replace('zt_', $this->config->db->prefix, $table);
             if(!$this->dbh->query($table)) return false;
diff --git a/module/upgrade/model.php b/module/upgrade/model.php
index 8bb8c1a010..31dfd47daa 100644
--- a/module/upgrade/model.php
+++ b/module/upgrade/model.php
@@ -158,6 +158,7 @@ class upgradeModel extends model
         case '5_0':
         case '5_1':
         case '5_2':
+        case '5_2_1':     $confirmContent .= file_get_contents($this->getUpgradeFile('5.2.1'));
         }
         return str_replace('zt_', $this->config->db->prefix, $confirmContent);
     }
@@ -612,13 +613,14 @@ class upgradeModel extends model
         {
             $line       = trim($line);
             $sqls[$key] = $line;
-            if(strpos($line, '--') !== false or empty($line)) unset($sqls[$key]);
+
+            /* Skip sql that is note. */
+            if(preg_match('/^--|^#|^\/\*/', $line) or empty($line)) unset($sqls[$key]);
         }
         $sqls = explode(';', join("\n", $sqls));
 
         foreach($sqls as $sql)
         {
-            $sql = trim($sql);
             if(empty($sql)) continue;
 
             if($mysqlVersion <= 4.1)