--- /home/all/SourceCode/yubikey/u2f4moz/ext/index.js	2016-02-18 21:11:23.129027842 +0000
+++ index.js	2016-02-19 15:44:35.949683893 +0000
@@ -65,6 +65,7 @@
 }
 
 function execBin(event, origin, challenges, checkSignChallenges, callbackid, worker, timeout) {
+  console.info("execBin() enter");
   let facetId = URL(origin);
   allValidAppIds(facetId, challenges).then(ch => {
     if (ch.length == 0) {
@@ -74,7 +75,7 @@
       });
       return;
     }
-    if (checkSignChallenges) {
+    if (checkSignChallenges && checkSignChallenges.length > 0) {
       allValidAppIds(facetId, checkSignChallenges).then(sch => {
         if (sch.length == 0) {
           worker.port.emit(event, callbackid, {
@@ -82,12 +83,16 @@
             errorMessage: "Invalid input"
           });
           return;
-      }
-      _execBin(event, origin, ch, sch, callbackid, worker, timeout);
-    });
-  } else
+        }
+        console.info("execBin() calling _execBin(check-sign)");
+        _execBin(event, origin, ch, sch, callbackid, worker, timeout);
+      });
+    } else {
+    console.info("execBin() calling _execBin(no-check-sign)");
     _execBin(event, origin, ch, null, callbackid, worker, timeout);
+    }
   });
+  console.info("execBin() leave");
 }
 
 function _execBin(event, origin, challenges, checkSignChallenges, callbackid, worker, timeout) {