diff --git a/background/background.js b/background/background.js
index cbd672ce..434921e4 100644
--- a/background/background.js
+++ b/background/background.js
@@ -13,7 +13,10 @@ window.API_METHODS = Object.assign(window.API_METHODS || {}, {
   saveStyle,
   deleteStyle,
 
-  download:    msg => download(msg.url),
+  download(msg) {
+    delete msg.method;
+    return download(msg.url, msg);
+  },
   getPrefs:    () => prefs.getAll(),
   healthCheck: () => dbExec().then(() => true),
 
diff --git a/content/install-hook-userstyles.js b/content/install-hook-userstyles.js
index f25ba3d0..5fe37747 100644
--- a/content/install-hook-userstyles.js
+++ b/content/install-hook-userstyles.js
@@ -219,7 +219,12 @@
       if (url.startsWith('#')) {
         resolve(document.getElementById(url.slice(1)).textContent);
       } else {
-        chrome.runtime.sendMessage({method: 'download', url}, result => {
+        chrome.runtime.sendMessage({
+          url,
+          method: 'download',
+          // USO can't handle POST requests for style json
+          body: null,
+        }, result => {
           const error = result && result.__ERROR__;
           if (error) {
             alert('Error' + (error ? '\n' + error : ''));