diff --git a/x509roots/gen_fallback_bundle.go b/x509roots/gen_fallback_bundle.go
index 41fab369f7..c3e562febc 100644
--- a/x509roots/gen_fallback_bundle.go
+++ b/x509roots/gen_fallback_bundle.go
@@ -2,8 +2,8 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-//go:build gen
-// +build gen
+//go:build generate
+// +build generate
 
 //go:generate go run gen_fallback_bundle.go