diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index 5159685..d099e97 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -906,7 +906,7 @@
     default:
     unimplemented:
         gemu_log("Unsupported setsockopt level=%d optname=%d \n", level, optname);
-        ret = -TARGET_ENOSYS;
+        ret = -TARGET_ENOPROTOOPT;
     }
     return ret;
 }