diff --git a/docs/device/crocodile-clips.md b/docs/device/crocodile-clips.md
index 01196b32..780acae0 100644
--- a/docs/device/crocodile-clips.md
+++ b/docs/device/crocodile-clips.md
@@ -11,9 +11,7 @@ This example displays a random number every time the crocodile clip holds  `GND`
 
 ### Connecting Crocodile Clips
 
-![](/static/mb/crocodile-clips-1.jpg)
 
-![](/static/mb/crocodile-clips-2.jpg)
 
 ### Lessons
 
diff --git a/libs/microbit/control.cpp b/libs/microbit/control.cpp
index 7556c3ae..2d8cc1f5 100644
--- a/libs/microbit/control.cpp
+++ b/libs/microbit/control.cpp
@@ -163,4 +163,12 @@ namespace control {
     StringData* deviceName() {
         return ManagedString(microbit_friendly_name()).leakData();        
     }
+    
+    /**
+    * Derive a unique, consistent serial number of this device from internal data.
+    */
+    //%
+    int deviceSerialNumber() {
+        return microbit_serial_number();
+    }
 }
diff --git a/libs/microbit/core.cpp b/libs/microbit/core.cpp
index 5179f490..b74c3cc5 100644
--- a/libs/microbit/core.cpp
+++ b/libs/microbit/core.cpp
@@ -301,4 +301,18 @@ namespace pxtrt {
   {
     microbit_panic(code);
   }
+
+  //
+  // Debugger
+  //
+
+  //%
+  uint32_t getNumGlobals() {
+    return numGlobals;
+  }
+
+  //%
+  void* getGlobalsPtr() {
+    return globals;
+  }
 }
diff --git a/libs/microbit/shims.d.ts b/libs/microbit/shims.d.ts
index bf33e2be..84c4ff0d 100644
--- a/libs/microbit/shims.d.ts
+++ b/libs/microbit/shims.d.ts
@@ -348,6 +348,12 @@ declare namespace control {
      */
     //% blockId="control_device_name" block="device name" weight=10 shim=control::deviceName
     function deviceName(): string;
+
+    /**
+     * Derive a unique, consistent serial number of this device from internal data.
+     */
+    //% shim=control::deviceSerialNumber
+    function deviceSerialNumber(): number;
 }
 
 
diff --git a/package.json b/package.json
index cab56e15..245a7d2c 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "pxt-microbit",
-  "version": "0.2.91",
+  "version": "0.2.92",
   "description": "BBC micro:bit target for PXT",
   "keywords": [
     "JavaScript",
@@ -29,6 +29,6 @@
     "typescript": "^1.8.7"
   },
   "dependencies": {
-    "pxt-core": "0.2.99"
+    "pxt-core": "0.2.100"
   }
 }
diff --git a/pxtarget.json b/pxtarget.json
index 949ac2d2..e1dff78d 100644
--- a/pxtarget.json
+++ b/pxtarget.json
@@ -57,7 +57,10 @@
         "deployDrives": "^MICROBIT"
     },
     "runtime": {
-      "mathBlocks": true
+      "mathBlocks": true,
+      "loopBlocks": true,
+      "logicBlocks": true,
+      "variablesBlocks": true
     },
     "simulator": {
         "autoRun": true