Preserve RRD preview frames and clarify onboard K1 status

tests/test_ble_scanner.py

@@ -1702,3 +1702,21 @@ def test_exact_session_invalidation_does_not_clear_new_scan_handle() -> None:
         ) is not None
 
     asyncio.run(scenario())
+
+
+@pytest.mark.parametrize("platform,present", [("linux", True), ("linux", False), ("darwin", False)])
+def test_status_read_native_cache_check_is_linux_only(monkeypatch, platform, present):
+    from types import SimpleNamespace
+
+    calls = []
+    device = BLEDevice("AA:BB:CC:DD:EE:FF", "synthetic", {"path": "/synthetic/bluez"})
+
+    async def retrieve(address, details):
+        calls.append((address, details))
+        return device if present else None
+
+    monkeypatch.setattr(scanner_module, "sys", SimpleNamespace(platform=platform))
+    monkeypatch.setattr(scanner_module, "_retrieve_bluez_device", retrieve)
+    assert asyncio.run(scanner_module.status_read_device_is_current(device)) is (
+        present or platform == "darwin")
+    assert len(calls) == (1 if platform == "linux" else 0)