diff --git a/plugins/ifx.c b/plugins/ifx.c
index 451658cd..311de34a 100644
--- a/plugins/ifx.c
+++ b/plugins/ifx.c
@@ -166,6 +166,9 @@ static void xsim_notify(GAtResult *result, gpointer user_data)
 			data->have_sim = TRUE;
 		}
 		break;
+	default:
+		ofono_warn("Unknown SIM state %d received", state);
+		break;
 	}
 }