diff --git a/tests/integration/test_logger_buffered_recursion_guard.py b/tests/integration/test_logger_buffered_recursion_guard.py
index 152e204214..5bef915b28 100644
--- a/tests/integration/test_logger_buffered_recursion_guard.py
+++ b/tests/integration/test_logger_buffered_recursion_guard.py
@@ -45,17 +45,11 @@ async def test_logger_buffered_recursion_guard(
     api_client_connected: APIClientConnectedFactory,
 ) -> None:
     """Buffered (non-main-thread) log messages survive a re-entrant main-task log."""
-    console_lines: list[str] = []
     api_messages: list[str] = []
-    test_complete_event = asyncio.Event()
-
-    def line_callback(line: str) -> None:
-        console_lines.append(line)
-        if "RACE_TEST_COMPLETE" in line:
-            test_complete_event.set()
+    all_drained = asyncio.Event()
 
     async with (
-        run_compiled(yaml_config, line_callback=line_callback),
+        run_compiled(yaml_config),
         api_client_connected() as client,
     ):
         device_info = await client.device_info()
@@ -65,8 +59,17 @@ async def test_logger_buffered_recursion_guard(
         # Subscribe over the API: this is the exact path that crashed in the field
         # (the API log callback runs during the buffered drain). The API message field
         # preserves embedded newlines, so it reliably exposes a clobbered buffer.
+        #
+        # Every buffered thread message is delivered here whether it survives intact or
+        # gets clobbered (a clobbered message still carries its THREADMSG payload), so
+        # counting THREADMSG occurrences is a deterministic "drain complete" signal: no
+        # arbitrary sleep, no dependence on the fix being present.
         def on_log(msg) -> None:
-            api_messages.append(msg.message.decode("utf-8", errors="replace"))
+            text = msg.message.decode("utf-8", errors="replace")
+            api_messages.append(text)
+            received = sum(len(THREAD_MSG_PATTERN.findall(m)) for m in api_messages)
+            if received >= NUM_MESSAGES:
+                all_drained.set()
 
         client.subscribe_logs(on_log, log_level=LogLevel.LOG_LEVEL_VERY_VERBOSE)
 
@@ -75,19 +78,16 @@ async def test_logger_buffered_recursion_guard(
         assert buttons, "Could not find Start Race Test button"
         client.button_command(buttons[0].key)
 
-        # RACE_TEST_COMPLETE is logged from the main task, so it arrives even if the
-        # buffered path is corrupted. The buffered messages are drained afterwards.
+        # Wait until every buffered thread message has been delivered over the API.
         try:
-            await asyncio.wait_for(test_complete_event.wait(), timeout=30.0)
+            await asyncio.wait_for(all_drained.wait(), timeout=30.0)
         except TimeoutError:
+            received = sum(len(THREAD_MSG_PATTERN.findall(m)) for m in api_messages)
             pytest.fail(
-                "Test did not complete within timeout; device likely crashed or hung. "
-                f"Collected {len(console_lines)} console lines."
+                f"Only {received}/{NUM_MESSAGES} thread messages arrived before timeout; "
+                "device likely crashed or hung."
             )
 
-        # Allow the buffered messages to drain after the thread joined.
-        await asyncio.sleep(0.5)
-
     intact: set[int] = set()
     contaminated: list[str] = []
     for raw in api_messages: