diff --git a/pxtarget.json b/pxtarget.json
index 586e2fa88a..5bf1984cf2 100644
--- a/pxtarget.json
+++ b/pxtarget.json
@@ -269,6 +269,7 @@
                 "permanent": true
             }
         },
+        "testSimulatorExtensions": {},
         "boardDefinition": {
             "visual": "microbit",
             "gpioPinBlocks": [
diff --git a/targetconfig.json b/targetconfig.json
index cbf90fbe8f..27d1845363 100644
--- a/targetconfig.json
+++ b/targetconfig.json
@@ -467,7 +467,7 @@
             "davidnsousa/sonification": { "tags": [ "Software" ] },
             "eanders-ms/simx-sample": {
                 "simx": {
-                    "sha": "611e641a4b80d979235dd9ac267d0a707c129a85",
+                    "sha": "6555401f995fac26ebafbaf1f1b1261ae72a05b3",
                     "devUrl": "http://localhost:5173"
                 }
             }