diff --git a/application/controllers/Qso.php b/application/controllers/Qso.php
index 0a02437e9..a5a33f504 100644
--- a/application/controllers/Qso.php
+++ b/application/controllers/Qso.php
@@ -21,7 +21,12 @@ class QSO extends CI_Controller {
         // Getting the live/post mode from GET command
         // 0 = live
         // 1 = post (manual)
-        $data['manual_mode'] = $this->security->xss_clean($this->input->get('manual'));
+        $get_manual_mode = $this->security->xss_clean($this->input->get('manual'));
+        if ($get_manual_mode == '0' || $get_manual_mode == '1') {
+            $data['manual_mode'] = $get_manual_mode;
+        } else {
+            show_404();
+        }
 
 		$data['active_station_profile'] = $this->stations->find_active();