How to make external C# dll library loadable (reflection) on iPhone?

Hello,

My dll is generated from a simple class:

   using UnityEngine;
 
   public class TestDll : MonoBehaviour {
       public void Awake() {
         Debug.Log("-> TestDll.Awake()");
       }
       public void Start() {
         Debug.Log("-> TestDll.Start()");
      }
     public void Test() {
         Debug.Log("-> TestDll.Text()");
     }
   }

I put the dll under application's Document folder on iPhone, and use folloing code to load it:

   Assembly assem = Assembly.Load(File.ReadAllBytes(Application.persistentDataPath + "/TestDll.dll"));

But I got error:

Non platform assembly: data-0x31c7e00 (this message is harmless) Failed to load AOT module 'data-0x31c7e00.dylib' in aot-only mode.

Then I did "mono --aot=full Test.dll" in Cygwin, and replaced it on iPhone, I got another error:

Non platform assembly: data-0xb16b000 (this message is harmless) Unhandled Exception: System.BadImageFormatException:

I googled, but didn't find answers.

Has anyone tried the same thing before? How did you make it?

Thank you