diff --git a/src/crypto/internal/fips/sha256/_asm/sha256block_amd64_asm.go b/src/crypto/internal/fips/sha256/_asm/sha256block_amd64_asm.go
index 24256185bc..3f5d5bdc23 100644
--- a/src/crypto/internal/fips/sha256/_asm/sha256block_amd64_asm.go
+++ b/src/crypto/internal/fips/sha256/_asm/sha256block_amd64_asm.go
@@ -5,12 +5,14 @@
 package main
 
 import (
+	"os"
+
 	. "github.com/mmcloughlin/avo/build"
 	. "github.com/mmcloughlin/avo/operand"
 	. "github.com/mmcloughlin/avo/reg"
 )
 
-//go:generate go run . -out ../sha256block_amd64.s -pkg sha256
+//go:generate go run . -out ../sha256block_amd64.s
 
 // SHA256 block routine. See sha256block.go for Go equivalent.
 //
@@ -53,7 +55,11 @@ import (
 // H7 = h + H7
 
 func main() {
-	Package("crypto/sha256")
+	// https://github.com/mmcloughlin/avo/issues/450
+	os.Setenv("GOOS", "linux")
+	os.Setenv("GOARCH", "amd64")
+
+	Package("crypto/internal/fips/sha256")
 	ConstraintExpr("!purego")
 	blockAMD64()
 	blockAVX2()
diff --git a/src/crypto/internal/fips/sha256/sha256block_amd64.s b/src/crypto/internal/fips/sha256/sha256block_amd64.s
index 7d9ed5acea..ce0ad4f887 100644
--- a/src/crypto/internal/fips/sha256/sha256block_amd64.s
+++ b/src/crypto/internal/fips/sha256/sha256block_amd64.s
@@ -1,4 +1,4 @@
-// Code generated by command: go run sha256block_amd64_asm.go -out ../sha256block_amd64.s -pkg sha256. DO NOT EDIT.
+// Code generated by command: go run sha256block_amd64_asm.go -out ../sha256block_amd64.s. DO NOT EDIT.
 
 //go:build !purego
 
diff --git a/src/crypto/internal/fips/sha3/_asm/keccakf_amd64_asm.go b/src/crypto/internal/fips/sha3/_asm/keccakf_amd64_asm.go
index 06e2db3a44..bdaafb72c5 100644
--- a/src/crypto/internal/fips/sha3/_asm/keccakf_amd64_asm.go
+++ b/src/crypto/internal/fips/sha3/_asm/keccakf_amd64_asm.go
@@ -8,13 +8,15 @@
 package main
 
 import (
+	"os"
+
 	. "github.com/mmcloughlin/avo/build"
 	. "github.com/mmcloughlin/avo/operand"
 	. "github.com/mmcloughlin/avo/reg"
 	_ "golang.org/x/crypto/sha3"
 )
 
-//go:generate go run . -out ../keccakf_amd64.s -pkg sha3
+//go:generate go run . -out ../sha3_amd64.s
 
 // Round Constants for use in the ι step.
 var RoundConstants = [24]uint64{
@@ -100,7 +102,11 @@ const (
 )
 
 func main() {
-	Package("golang.org/x/crypto/sha3")
+	// https://github.com/mmcloughlin/avo/issues/450
+	os.Setenv("GOOS", "linux")
+	os.Setenv("GOARCH", "amd64")
+
+	Package("crypto/internal/fips/sha3")
 	ConstraintExpr("!purego")
 	keccakF1600()
 	Generate()
diff --git a/src/crypto/internal/fips/sha3/sha3_amd64.s b/src/crypto/internal/fips/sha3/sha3_amd64.s
index 7f9a315157..3137e2d6cf 100644
--- a/src/crypto/internal/fips/sha3/sha3_amd64.s
+++ b/src/crypto/internal/fips/sha3/sha3_amd64.s
@@ -1,4 +1,4 @@
-// Code generated by command: go run keccakf_amd64_asm.go -out ../keccakf_amd64.s -pkg sha3. DO NOT EDIT.
+// Code generated by command: go run keccakf_amd64_asm.go -out ../sha3_amd64.s. DO NOT EDIT.
 
 //go:build !purego
 
diff --git a/src/crypto/internal/fips/sha512/_asm/sha512block_amd64_asm.go b/src/crypto/internal/fips/sha512/_asm/sha512block_amd64_asm.go
index c0959714d0..fa540d0f2d 100644
--- a/src/crypto/internal/fips/sha512/_asm/sha512block_amd64_asm.go
+++ b/src/crypto/internal/fips/sha512/_asm/sha512block_amd64_asm.go
@@ -5,12 +5,14 @@
 package main
 
 import (
+	"os"
+
 	. "github.com/mmcloughlin/avo/build"
 	. "github.com/mmcloughlin/avo/operand"
 	. "github.com/mmcloughlin/avo/reg"
 )
 
-//go:generate go run . -out ../sha512block_amd64.s -pkg sha512
+//go:generate go run . -out ../sha512block_amd64.s
 
 // SHA512 block routine. See sha512block.go for Go equivalent.
 //
@@ -138,7 +140,11 @@ var _K = []uint64{
 }
 
 func main() {
-	Package("crypto/sha512")
+	// https://github.com/mmcloughlin/avo/issues/450
+	os.Setenv("GOOS", "linux")
+	os.Setenv("GOARCH", "amd64")
+
+	Package("crypto/internal/fips/sha512")
 	ConstraintExpr("!purego")
 	blockAMD64()
 	blockAVX2()
diff --git a/src/crypto/internal/fips/sha512/sha512block_amd64.s b/src/crypto/internal/fips/sha512/sha512block_amd64.s
index ffccdf229f..534563ee14 100644
--- a/src/crypto/internal/fips/sha512/sha512block_amd64.s
+++ b/src/crypto/internal/fips/sha512/sha512block_amd64.s
@@ -1,4 +1,4 @@
-// Code generated by command: go run sha512block_amd64_asm.go -out ../sha512block_amd64.s -pkg sha512. DO NOT EDIT.
+// Code generated by command: go run sha512block_amd64_asm.go -out ../sha512block_amd64.s. DO NOT EDIT.
 
 //go:build !purego