diff --git a/mozilla/extensions/irc/js/lib/utils.js b/mozilla/extensions/irc/js/lib/utils.js
index 3f67dfa49fa..7942a96ff41 100644
--- a/mozilla/extensions/irc/js/lib/utils.js
+++ b/mozilla/extensions/irc/js/lib/utils.js
@@ -274,7 +274,7 @@ function ecmaUnescape(str)
 {
     function replaceEscapes(seq)
     {
-        var ary = seq.match(/([\da-f]{1,2})(.*)|u([\da-f]{1,4})/);
+        var ary = seq.match(/([\da-f]{1,2})(.*)|u([\da-f]{1,4})/i);
         if (!ary)
             return "<ERROR>";