diff --git a/repos/libports/src/lib/libc/vfs_plugin.cc b/repos/libports/src/lib/libc/vfs_plugin.cc
index 3e4bc1064d..a07c71f852 100644
--- a/repos/libports/src/lib/libc/vfs_plugin.cc
+++ b/repos/libports/src/lib/libc/vfs_plugin.cc
@@ -2066,7 +2066,7 @@ int Libc::Vfs_plugin::fcntl(File_descriptor *fd, int cmd, long arg)
 		break;
 	}
 
-	error("fcntl(): command ", cmd, " not supported - vfs");
+	error("fcntl(): command ", Hex(cmd), " not supported - vfs");
 	return Errno(EINVAL);
 }