diff --git a/editor.html b/editor.html
index 4c147a9..c59e79f 100644
--- a/editor.html
+++ b/editor.html
@@ -1238,7 +1238,9 @@ async function updateFirmware() {   // A/B firmware update over USB-MIDI: push t
     return;
   }
   console.log("[fw] pushing", b64.length, "base64 chars...");
+  clearInterval(_midiBeat); _midiBeat = 0;          // pause the Device-audio heartbeat (its MIDI traffic stalls the push)
   const err = await _pushFirmware(b64);
+  if (_midiOn) _heartbeat(true);                    // resume it afterwards
   console.log("[fw] push result:", err || "OK");
   if (err) return alert("Update didn't complete (" + err + ").\n\nThe device kept its working firmware — nothing was installed. " +
       "Make sure it's plugged in and NOT in editor mode (don't hold A), then retry.");