diff -r 8e42a376da73 -r c5720b98ab4e rt/emul/mini/src/main/java/java/lang/Boolean.java
--- a/rt/emul/mini/src/main/java/java/lang/Boolean.java	Thu May 16 08:49:55 2013 +0200
+++ b/rt/emul/mini/src/main/java/java/lang/Boolean.java	Mon May 26 14:33:42 2014 +0200
@@ -289,8 +289,9 @@
         initValueOf();
     }
     @JavaScriptBody(args = {  }, body = 
-        "vm.java_lang_Boolean(false)" +
-        ".valueOf = function() { return this._value() ? true : false; };"
+        "var bc = vm.java_lang_Boolean(false);\n" +
+        "bc.valueOf = function() { return this._value() ? true : false; };\n" +
+        "bc.toString = function() { return this.valueOf().toString(); };\n"
     )
     private native static void initValueOf();
 }