diff --git a/tools/kwboot.c b/tools/kwboot.c
index 1ba5ded..7fa742d 100644
--- a/tools/kwboot.c
+++ b/tools/kwboot.c
@@ -558,7 +558,8 @@
 		}
 	} while (quit[s] != 0);
 
-	tcsetattr(in, TCSANOW, &otio);
+	if (in >= 0)
+		tcsetattr(in, TCSANOW, &otio);
 out:
 	return rc;
 }