diff --git a/install.xml b/install.xml
index e3ffb8d..bcb4354 100644
--- a/install.xml
+++ b/install.xml
@@ -9,7 +9,7 @@
     <file path="catalog/model/checkout/order.php">
         <operation error="skip">
             <search><![CDATA[$this->db->query("UPDATE " . DB_PREFIX . "product SET quantity = (quantity - " . (int)$order_product['quantity'] . ") WHERE product_id = '" . (int)$order_product['product_id'] . "' AND subtract = '1'");]]></search>
-            <add position="replace"><![CDATA[$this->db->query("UPDATE " . DB_PREFIX . "product SET quantity = (quantity - " . (int)$order_product['quantity'] . "), status = IF((quantity - " . (int)$order_product['quantity'] . ") = 0, 0, 1) WHERE product_id = '" . (int)$order_product['product_id'] . "' AND subtract = '1'");]]></add>
+            <add position="replace"><![CDATA[$this->db->query("UPDATE " . DB_PREFIX . "product SET quantity = (quantity - " . (int)$order_product['quantity'] . "), status = IF((quantity - " . (int)$order_product['quantity'] . ") <= 0, 0, 1) WHERE product_id = '" . (int)$order_product['product_id'] . "' AND subtract = '1'");]]></add>
         </operation>
         <operation error="skip">
             <search><![CDATA[$this->db->query("UPDATE `" . DB_PREFIX . "product` SET quantity = (quantity + " . (int)$order_product['quantity'] . ") WHERE product_id = '" . (int)$order_product['product_id'] . "' AND subtract = '1'");]]></search>