diff --git a/platform/chromium/vapi-common.js b/platform/chromium/vapi-common.js
index 21a8fa3de..57a9a5b9b 100644
--- a/platform/chromium/vapi-common.js
+++ b/platform/chromium/vapi-common.js
@@ -50,7 +50,12 @@ vAPI.webextFlavor = {
     };
 
     // This is always true.
-    soup.add('ublock');
+    soup.add('ublock').add('webext');
+
+    // Whether this is a dev build.
+    if ( /^\d+\.\d+\.\d+\D/.test(chrome.runtime.getManifest().version) ) {
+        soup.add('devbuild');
+    }
 
     if ( /\bMobile\b/.test(ua) ) {
         soup.add('mobile');
diff --git a/src/js/assets.js b/src/js/assets.js
index 904885a3a..397ae5c5f 100644
--- a/src/js/assets.js
+++ b/src/js/assets.js
@@ -909,15 +909,10 @@ var updateFirst = function() {
     //   Allow self-hosted dev build to update: if update_url is present but
     //   null, assume the extension is hosted on AMO.
     if ( noRemoteResources === undefined ) {
-        var manifest =
-            typeof browser === 'object' &&
-            browser.runtime.getManifest();
         noRemoteResources =
             vAPI.webextFlavor.soup.has('firefox') &&
-            manifest instanceof Object &&
-            manifest.applications instanceof Object &&
-            manifest.applications.gecko instanceof Object &&
-            manifest.applications.gecko.update_url === null;
+            vAPI.webextFlavor.soup.has('webext') &&
+            vAPI.webextFlavor.soup.has('devbuild') === false;
     }
     updaterStatus = 'updating';
     updaterFetched.clear();