diff --git a/supervisor/api/const.py b/supervisor/api/const.py
index a49b88f94..6eb65df70 100644
--- a/supervisor/api/const.py
+++ b/supervisor/api/const.py
@@ -87,4 +87,4 @@ class DetectBlockingIO(StrEnum):
 
     OFF = "off"
     ON = "on"
-    ON_AT_STARTUP = "on_at_startup"
+    ON_AT_STARTUP = "on-at-startup"
diff --git a/tests/api/test_supervisor.py b/tests/api/test_supervisor.py
index 251ff4eef..07032d88b 100644
--- a/tests/api/test_supervisor.py
+++ b/tests/api/test_supervisor.py
@@ -271,7 +271,7 @@ async def test_api_supervisor_options_country(api_client: TestClient, coresys: C
 
 @pytest.mark.parametrize(
     ("blockbuster", "option_value", "config_value"),
-    [("no_blockbuster", "on", False), ("no_blockbuster", "on_at_startup", True)],
+    [("no_blockbuster", "on", False), ("no_blockbuster", "on-at-startup", True)],
     indirect=["blockbuster"],
 )
 async def test_api_supervisor_options_blocking_io(