diff --git a/book/vol1/day15.md b/book/vol1/day15.md
index e72f93a..80199b6 100644
--- a/book/vol1/day15.md
+++ b/book/vol1/day15.md
@@ -116,7 +116,7 @@ fn getattr(&mut self, _req: &Request, ino: u64, reply: ReplyAttr) {
     if ino == 1 {
         reply.attr(&ttl, &attr);
     } else {
-        reply.error(ENOSYS);
+        reply.error(ENOENT);
     }
 }
 ```