diff --git a/.github/workflows/ci_qemu.yml b/.github/workflows/ci_qemu.yml
index 8610c0c..d4af520 100644
--- a/.github/workflows/ci_qemu.yml
+++ b/.github/workflows/ci_qemu.yml
@@ -14,7 +14,7 @@ jobs:
   test:
     strategy:
       matrix:
-        go-version: [1.21.x]
+        go-version: [1.18.x]
         arch: [arm64]  
     runs-on: ubuntu-latest
     steps:
diff --git a/base64_arm64_test.go b/base64_arm64_test.go
index 795c54a..d80ad68 100644
--- a/base64_arm64_test.go
+++ b/base64_arm64_test.go
@@ -13,7 +13,7 @@ func TestStdEncodeSIMD(t *testing.T) {
 		expected := []byte(p.encoded)
 		dst := make([]byte, len(expected))
 
-		ret := encodeAsm(dst, src, &encodeStd)
+		ret := encodeAsm(dst, src, &StdEncoding.encode)
 		if ret != len(expected) {
 			t.Fatalf("should return %v", len(expected))
 		}