diff --git a/src/lib9/open.c b/src/lib9/open.c
index b70a9a2..95d20d4 100644
--- a/src/lib9/open.c
+++ b/src/lib9/open.c
@@ -22,7 +22,7 @@
 		mode ^= ODIRECT;
 	}
 	if(mode){
-		werrstr("mode not supported");
+		werrstr("mode 0x%x not supported", mode);
 		return -1;
 	}
 	fd = open(name, umode);