diff --git a/apps/android/ChangeLog b/apps/android/ChangeLog
index 9ac11d75b..63645faf4 100644
--- a/apps/android/ChangeLog
+++ b/apps/android/ChangeLog
@@ -41,4 +41,8 @@
 0.38: Don't rewrite settings file on every boot!
 0.39: Move GB message handling into a library to reduce boot time from 40ms->13ms
 0.40: Ensure we send health 'activity' message to gadgetbridge (added 2v26)
-0.41: When using `actfetch`, fetch historical activity type too
\ No newline at end of file
+0.41: When using `actfetch`, fetch historical activity type too
+0.42: Add handling for android STREAM_MUSIC volume level info, emitting on
+      arrival. (Needs Gadgetbridge nightly (either flavor) for now, or stable
+      version 85 when it's out)
+
diff --git a/apps/android/lib.js b/apps/android/lib.js
index c2b3722b3..39dba448b 100644
--- a/apps/android/lib.js
+++ b/apps/android/lib.js
@@ -44,6 +44,10 @@ exports.gbHandler = (event) => {
     "musicinfo" : function() {
       require("messages").pushMessage(Object.assign(event, {t:"modify",id:"music",title:"Music"}));
     },
+    // {t:"audio", v:(percentage of max volume for android STREAM_MUSIC)}
+    "audio" : function() {
+      Bangle.emit("musicVolume", event.v);
+    },
     // {"t":"call","cmd":"incoming/end/start/outgoing","name":"Bob","number":"12421312"})
     "call" : function() {
       Object.assign(event, {
@@ -386,4 +390,4 @@ exports.overwriteGPS = () => { // if the overwrite option is set, call this on i
   setTimeout(()=>{
     if (!Bangle.isGPSOn()) require("android").gbSend({ t: "gps_power", status: false });
   },3000);
-};
\ No newline at end of file
+};
diff --git a/apps/android/metadata.json b/apps/android/metadata.json
index 2066a2133..32a46d531 100644
--- a/apps/android/metadata.json
+++ b/apps/android/metadata.json
@@ -2,7 +2,7 @@
   "id": "android",
   "name": "Android Integration",
   "shortName": "Android",
-  "version": "0.41",
+  "version": "0.42",
   "description": "Display notifications/music/etc sent from the Gadgetbridge app on Android. This replaces the old 'Gadgetbridge' Bangle.js widget.",
   "icon": "app.png",
   "tags": "tool,system,messages,notifications,gadgetbridge",
diff --git a/apps/setting/README.md b/apps/setting/README.md
index 00e46aa1f..bbc724083 100644
--- a/apps/setting/README.md
+++ b/apps/setting/README.md
@@ -18,7 +18,7 @@ See below for options under each heading:
 * **Clock** if you have more than one clock face, select the default one
 * **Launcher** if you have more than one app launcher, select the default one
 * **Date & Time** Configure the current time - Note that this can be done much more easily by choosing 'Set Time' from the App Loader
-* **Altitude** On Bangle.js 2, adjust the altitude (
+* **Altitude** On Bangle.js 2, calibrate the altitude (which varies depending on Air Pressure). Tap `Adjust Up`/`Adjust Down` to move the reported altitude by around 10m
 
 ## Alerts
 
diff --git a/core b/core
index 1cdcb3405..43dbadf5b 160000
--- a/core
+++ b/core
@@ -1 +1 @@
-Subproject commit 1cdcb3405f78ef35f231b9c3df501721bda75525
+Subproject commit 43dbadf5b9a41ff00aa6bef76d3360b510fb06a5
diff --git a/index.html b/index.html
index 608c90f91..8af9a6ec4 100644
--- a/index.html
+++ b/index.html
@@ -209,11 +209,15 @@
       </div>
     </footer>
 
-    <script src="webtools/puck.js"></script>
+    <script src="webtools/uart.js"></script>
+    <script src="core/js/utils.js"></script>
+    <script>
+      UART.ports = UART.ports.filter(e => e.includes("Bluetooth")); // all watches are Bluetooth
+      Const.CONNECTION_DEVICE = "Bluetooth"; // force Bluetooth because we know (don't look it up)
+    </script>
     <script src="webtools/heatshrink.js"></script>
     <script src="core/lib/marked.min.js"></script>
     <script src="core/lib/espruinotools.js"></script>
-    <script src="core/js/utils.js"></script>
     <script src="loader.js"></script>
     <script src="https://cdnjs.cloudflare.com/ajax/libs/jszip/3.7.1/jszip.min.js"></script> <!-- for backup.js -->
     <script src="backup.js"></script>
diff --git a/loader.js b/loader.js
index 578b4e1c4..9aca4e3e9 100644
--- a/loader.js
+++ b/loader.js
@@ -267,12 +267,16 @@ window.addEventListener('load', (event) => {
   // BLE Compatibility
   var selectBLECompat = document.getElementById("settings-ble-compat");
   if (selectBLECompat) {
-    Puck.increaseMTU = !SETTINGS.bleCompat;
+    function setBLECompat(compat) {
+      if ("undefined"!==typeof Puck) Puck.increaseMTU = !compat;
+      if ("undefined"!==typeof UART) UART.increaseMTU = !compat;
+    }
+    setBLECompat(SETTINGS.bleCompat);
     selectBLECompat.checked = !!SETTINGS.bleCompat;
     selectBLECompat.addEventListener("change",event=>{
       console.log("BLE compatibility mode "+(event.target.checked?"on":"off"));
       SETTINGS.bleCompat = event.target.checked;
-      Puck.increaseMTU = !SETTINGS.bleCompat;
+      setBLECompat(SETTINGS.bleCompat);
       saveSettings();
     });
   }
diff --git a/webtools b/webtools
index d659cfa05..27939deca 160000
--- a/webtools
+++ b/webtools
@@ -1 +1 @@
-Subproject commit d659cfa05e66c5c770659668e8eecaecd08f91bd
+Subproject commit 27939deca30abe8896a4e630e732e5cf4f9a3712