diff --git a/examples/bios/main.go b/examples/bios/main.go
index 4635b568..16def4aa 100644
--- a/examples/bios/main.go
+++ b/examples/bios/main.go
@@ -91,5 +91,8 @@ func main() {
 		if err != nil {
 			l.Error(err)
 		}
+	default:
+		l.Fatal("Unknown mode: " + *mode)
+
 	}
 }