diff --git a/xCAT-server/lib/xcat/plugins/openbmc.pm b/xCAT-server/lib/xcat/plugins/openbmc.pm
index 746de86a7..1c11b94ad 100644
--- a/xCAT-server/lib/xcat/plugins/openbmc.pm
+++ b/xCAT-server/lib/xcat/plugins/openbmc.pm
@@ -741,17 +741,17 @@ sub preprocess_request {
     # Request usage for openbmc sections only
     $usage_string = xCAT::Usage->parseCommand($command . ".openbmc", @exargs);
 
-    if ($usage_string =~ /cannot be found/) {
-        # Could not find usage for openbmc section, try getting usage for all sections
-        $usage_string = xCAT::Usage->parseCommand($command, @exargs);
-    }
-    else {
-        # Usage for openbmc section was extracted, append autogenerated usage for
-        # configured commands
-        $usage_string .= &build_config_api_usage($callback, $command);
-    }
-
     if ($usage_string) {
+        if ($usage_string =~ /cannot be found/) {
+            # Could not find usage for openbmc section, try getting usage for all sections
+            $usage_string = xCAT::Usage->parseCommand($command, @exargs);
+        }
+        else {
+            # Usage for openbmc section was extracted, append autogenerated usage for
+            # configured commands
+            $usage_string .= &build_config_api_usage($callback, $command);
+        }
+
         $callback->({ data => [$usage_string] });
         $request = {};
         return;