diff --git a/blake2b/blake2bAVX2_amd64.go b/blake2b/blake2bAVX2_amd64.go
index 56bfaaa17d..b7b8aa8d3f 100644
--- a/blake2b/blake2bAVX2_amd64.go
+++ b/blake2b/blake2bAVX2_amd64.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 go1.7 && amd64 && gc && !purego
-// +build go1.7,amd64,gc,!purego
+//go:build amd64 && gc && !purego
+// +build amd64,gc,!purego
 
 package blake2b
 
diff --git a/blake2b/blake2bAVX2_amd64.s b/blake2b/blake2bAVX2_amd64.s
index 4b9daa18d9..e1a1183996 100644
--- a/blake2b/blake2bAVX2_amd64.s
+++ b/blake2b/blake2bAVX2_amd64.s
@@ -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 go1.7 && amd64 && gc && !purego
-// +build go1.7,amd64,gc,!purego
+//go:build amd64 && gc && !purego
+// +build amd64,gc,!purego
 
 #include "textflag.h"
 
diff --git a/blake2b/blake2b_amd64.go b/blake2b/blake2b_amd64.go
deleted file mode 100644
index 5fa1b32841..0000000000
--- a/blake2b/blake2b_amd64.go
+++ /dev/null
@@ -1,25 +0,0 @@
-// Copyright 2016 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-//go:build !go1.7 && amd64 && gc && !purego
-// +build !go1.7,amd64,gc,!purego
-
-package blake2b
-
-import "golang.org/x/sys/cpu"
-
-func init() {
-	useSSE4 = cpu.X86.HasSSE41
-}
-
-//go:noescape
-func hashBlocksSSE4(h *[8]uint64, c *[2]uint64, flag uint64, blocks []byte)
-
-func hashBlocks(h *[8]uint64, c *[2]uint64, flag uint64, blocks []byte) {
-	if useSSE4 {
-		hashBlocksSSE4(h, c, flag, blocks)
-	} else {
-		hashBlocksGeneric(h, c, flag, blocks)
-	}
-}
diff --git a/blake2b/register.go b/blake2b/register.go
index 9d8633963c..54e446e1d2 100644
--- a/blake2b/register.go
+++ b/blake2b/register.go
@@ -2,9 +2,6 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-//go:build go1.9
-// +build go1.9
-
 package blake2b
 
 import (