diff --git a/unity/Assets/core/upm/Runtime/Src/Default/Native/PuertsDLL.cs b/unity/Assets/core/upm/Runtime/Src/Default/Native/PuertsDLL.cs
index bf95373b26..44e8be3031 100644
--- a/unity/Assets/core/upm/Runtime/Src/Default/Native/PuertsDLL.cs
+++ b/unity/Assets/core/upm/Runtime/Src/Default/Native/PuertsDLL.cs
@@ -9,6 +9,8 @@
 using System.Runtime.InteropServices;
 using System.Text;
 
+#if !PUERTS_IL2CPP_OPTIMIZATION || !ENABLE_IL2CPP
+
 namespace Puerts
 {
 #pragma warning disable 414
@@ -645,3 +647,5 @@ public static string GetJSStackTrace(IntPtr isolate)
         }
     }
 }
+
+#endif
diff --git a/unity/Assets/core/upm/Runtime/Src/IL2Cpp/Native/NativeAPI.cs b/unity/Assets/core/upm/Runtime/Src/IL2Cpp/Native/NativeAPI.cs
index 52facc6c00..7c9af112e8 100644
--- a/unity/Assets/core/upm/Runtime/Src/IL2Cpp/Native/NativeAPI.cs
+++ b/unity/Assets/core/upm/Runtime/Src/IL2Cpp/Native/NativeAPI.cs
@@ -5,6 +5,8 @@
 * This file is subject to the terms and conditions defined in file 'LICENSE', which is part of this source code package.
 */
 
+#if UNITY_2020_1_OR_NEWER
+#if PUERTS_IL2CPP_OPTIMIZATION && ENABLE_IL2CPP
 
 using System;
 using System.Runtime.InteropServices;
@@ -14,6 +16,17 @@
 
 namespace Puerts
 {
+#pragma warning disable 414
+    public class MonoPInvokeCallbackAttribute : System.Attribute
+    {
+        private Type type;
+        public MonoPInvokeCallbackAttribute(Type t)
+        {
+            type = t;
+        }
+    }
+#pragma warning restore 414
+
     public class NativeAPI
     {
 #if (UNITY_IPHONE || UNITY_TVOS || UNITY_WEBGL || UNITY_SWITCH) && !UNITY_EDITOR
@@ -428,3 +441,6 @@ public struct pesapi_ffi
         public pesapi_set_env_private_func set_env_private;
     }
 }
+
+#endif
+#endif