diff --git a/.env.example b/.env.example
index 7992804..65db35e 100644
--- a/.env.example
+++ b/.env.example
@@ -42,9 +42,9 @@ UART_RX_GPIO=21
 # ---------- Read-only development probe ----------
 # Keep disabled until a safe, conditioned front-panel signal is connected.
 PROBE_ENABLED=false
-# Required when PROBE_ENABLED=true. GPIO3 is a candidate on the C3 Super Mini,
-# but confirm the board routing and electrical interface before using it.
-PROBE_GPIO=
+# Required when PROBE_ENABLED=true. GPIO3 is the chosen candidate on the
+# ESP32-C3 Super Mini; confirm the electrical interface before using it.
+PROBE_GPIO=3
 # state | frequency | pulse | watch
 PROBE_MODE=frequency
 PROBE_INTERVAL_SECONDS=3
diff --git a/firmware/launcher.py b/firmware/launcher.py
index 912c137..278e7d7 100644
--- a/firmware/launcher.py
+++ b/firmware/launcher.py
@@ -197,6 +197,16 @@ def epoch_is_valid():
         return False
 
 
+def is_awaitable(value):
+    """Support CPython and MicroPython coroutine objects.
+
+    On the ESP32 MicroPython port, native coroutine objects expose ``send``
+    but not ``__await__``. Checking both lets application hooks be either
+    synchronous functions or ``async def`` coroutines.
+    """
+    return hasattr(value, "__await__") or hasattr(value, "send")
+
+
 class ActivityTracker:
     """Tracks idleness and protected/busy operations for safe OTA timing."""
 
@@ -816,7 +826,7 @@ async def run_async():
     # restore the previous launcher/app files.
     if hasattr(app, "setup"):
         result = app.setup(ctx)
-        if hasattr(result, "__await__"):
+        if is_awaitable(result):
             await result
     else:
         system.ready()
@@ -825,7 +835,7 @@ async def run_async():
         asyncio.create_task(updater.service())
 
     result = app.main(ctx)
-    if hasattr(result, "__await__"):
+    if is_awaitable(result):
         await result
     else:
         log("synchronous main() returned; async main() is recommended")
diff --git a/firmware/manifest.json b/firmware/manifest.json
index 1b3d10c..6eeea5c 100644
--- a/firmware/manifest.json
+++ b/firmware/manifest.json
@@ -1,11 +1,11 @@
 {
   "schema": 1,
-  "release": "0.1.2-probe.2",
+  "release": "0.1.3-probe.3",
   "files": [
     {
       "source": "firmware/launcher.py",
       "target": "/launcher.py",
-      "sha256": "f8ef1bba8e298877b39427870a10ea4784db33a943a5e10040bf652b4866cd2f"
+      "sha256": "e668276d99c5e78238fe9c4eb77acb5c055a4f0deabf272112ed4e0f2c1320ef"
     },
     {
       "source": "firmware/app/__init__.py",