diff --git a/www/js/interface.js b/www/js/interface.js
index cc242ef..8f678fb 100644
--- a/www/js/interface.js
+++ b/www/js/interface.js
@@ -398,7 +398,7 @@ const INTERFACE = {
                 }
 
                 let b_undo = document.getElementById("button-undo");
-                if(GAME_DATA.turn == 0 || INTERFACE_DATA.Ui.request_undo == 1) {
+                if(GAME_DATA.turn == 0 || GAME_DATA.state.code != 0 || INTERFACE_DATA.Ui.request_undo == 1) {
                     b_undo.setAttribute("disabled", "");
                     b_undo.removeAttribute("class");
                 } else {