diff --git a/.github/workflows/packages.yml b/.github/workflows/packages.yml
index adb03b0..c648546 100644
--- a/.github/workflows/packages.yml
+++ b/.github/workflows/packages.yml
@@ -699,3 +699,37 @@ jobs:
       - name: Test
         working-directory: curve25519-voi
         run: go test ./...
+  golang-crypto-curve25519:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Install Go
+        uses: actions/setup-go@37335c7bb261b353407cff977110895fa0b4f7d8 # v2.1.3
+        with:
+          go-version: 1.17.x
+      - name: Checkout avo
+        uses: actions/checkout@5a4ac9002d0be2fb38bd78e4b4dbde5606d7042f # v2.3.4
+        with:
+          path: avo
+          persist-credentials: false
+      - name: Checkout golang/crypto
+        uses: actions/checkout@5a4ac9002d0be2fb38bd78e4b4dbde5606d7042f # v2.3.4
+        with:
+          repository: golang/crypto
+          ref: 089bfa5675191fd96a44247682f76ebca03d7916
+          path: crypto
+          persist-credentials: false
+      - name: Avo Module Replacement
+        working-directory: crypto/curve25519/internal/field/_asm
+        run: |
+          go mod edit -modfile=go.mod -require=github.com/mmcloughlin/avo@v0.0.0-00010101000000-000000000000
+          go mod edit -modfile=go.mod -replace=github.com/mmcloughlin/avo=${{ github.workspace }}/avo
+          go mod tidy -modfile=go.mod
+      - name: Generate
+        working-directory: crypto/curve25519/internal/field/_asm
+        run: go generate -v -x
+      - name: Diff
+        working-directory: crypto/curve25519
+        run: git diff
+      - name: Test
+        working-directory: crypto/curve25519
+        run: go test ./...
diff --git a/tests/thirdparty/packages.json b/tests/thirdparty/packages.json
index 69518c7..57a51d3 100644
--- a/tests/thirdparty/packages.json
+++ b/tests/thirdparty/packages.json
@@ -441,5 +441,22 @@
                 ]
             }
         ]
+    },
+    {
+        "repository": {
+            "owner": "golang",
+            "name": "crypto"
+        },
+        "version": "089bfa5675191fd96a44247682f76ebca03d7916",
+        "pkg": "curve25519",
+        "module": "internal/field/_asm/go.mod",
+        "generate": [
+            {
+                "dir": "internal/field/_asm",
+                "commands": [
+                    "go generate -v -x"
+                ]
+            }
+        ]
     }
 ]