diff --git a/poly1305/sum_arm.s b/poly1305/sum_arm.s
index 25bb987..c09f182 100644
--- a/poly1305/sum_arm.s
+++ b/poly1305/sum_arm.s
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-#include "textflags.h"
+#include "textflag.h"
 
 // This code was translated into a form compatible with 5a from the public
 // domain source by Andrew Moon: github.com/floodyberry/poly1305-opt/blob/master/app/extensions/poly1305.