diff --git a/common/main.js b/common/main.js
index af756615..a747c87f 100644
--- a/common/main.js
+++ b/common/main.js
@@ -77,7 +77,7 @@ LazyLoad.js([
 
     goog.platform = () => {
         const userAgent = navigator.userAgent;
-        if (userAgent.indexOf('Mobile') !== -1) return 'mobile';
+        if (!navigator.serial) return 'mobile';
         if (userAgent.indexOf('Windows NT') !== -1) return 'win32';
         if (userAgent.indexOf('Mac') !== -1) return 'darwin';
         if (userAgent.indexOf('X11') !== -1) return 'linux';
@@ -96,7 +96,7 @@ LazyLoad.js([
             else if (userAgent.indexOf('Windows NT 6.1') != -1) os = 'win7';
             else if (userAgent.indexOf('Windows NT 6.0') != -1) os = 'winvista';
             else if (userAgent.indexOf('Windows NT 5.1') != -1) os = 'winxp';
-        } else if (navigator.serial==undefined) {
+        } else if (!navigator.serial) {
             os = 'android';
         } else if (platform.includes('iphone') || platform.includes('ipad') || platform.includes('ipod')) {
             os = 'ios';
diff --git a/common/modules/mixly-modules/web/serial.js b/common/modules/mixly-modules/web/serial.js
index 06944322..72faac16 100644
--- a/common/modules/mixly-modules/web/serial.js
+++ b/common/modules/mixly-modules/web/serial.js
@@ -35,7 +35,7 @@ if (platform === 'win32' && fullPlatform !== 'win10') {
             Device = USBMini;
         }
     }
-} else if (['android', 'ios'].includes(fullPlatform)) {
+} else if (platform === 'mobile') {
     if (['BBC micro:bit', 'Mithon CC'].includes(BOARD.boardType)) {
         Device = USB;
     } else {