diff --git a/Assets/UniGLTF/Runtime/UniGLTF/Format/IStorage.cs b/Assets/UniGLTF/Runtime/UniGLTF/Format/IStorage.cs
index d12009ce2..b7495b2be 100644
--- a/Assets/UniGLTF/Runtime/UniGLTF/Format/IStorage.cs
+++ b/Assets/UniGLTF/Runtime/UniGLTF/Format/IStorage.cs
@@ -4,7 +4,7 @@ namespace UniGLTF
 {
     public interface IStorage
     {
-        ArraySegment<Byte> Get(string url);
+        ArraySegment<Byte> Get(string url = default);
 
         /// <summary>
         /// Get original filepath if exists
diff --git a/Assets/UniGLTF/Runtime/UniGLTF/IO/GltfData.cs b/Assets/UniGLTF/Runtime/UniGLTF/IO/GltfData.cs
index 67534b39b..8196458d5 100644
--- a/Assets/UniGLTF/Runtime/UniGLTF/IO/GltfData.cs
+++ b/Assets/UniGLTF/Runtime/UniGLTF/IO/GltfData.cs
@@ -1,9 +1,6 @@
 using System;
 using System.Collections.Generic;
-using System.IO;
 using System.Linq;
-using System.Text;
-using UnityEngine;
 
 namespace UniGLTF
 {
@@ -31,6 +28,12 @@ namespace UniGLTF
         /// </summary>
         public IReadOnlyList<GlbChunk> Chunks { get; }
 
+        /// <summary>
+        /// Bin chunk bytes
+        /// </summary>
+        /// <returns></returns>
+        public ArraySegment<byte> Bin => Chunks.First(x => x.ChunkType == GlbChunkType.BIN).Bytes;
+
         /// <summary>
         /// URI access
         /// </summary>
diff --git a/Assets/UniGLTF/Runtime/UniGLTF/IO/Parser/GlbBinaryParser.cs b/Assets/UniGLTF/Runtime/UniGLTF/IO/Parser/GlbBinaryParser.cs
index e14fe83d8..6785a6f22 100644
--- a/Assets/UniGLTF/Runtime/UniGLTF/IO/Parser/GlbBinaryParser.cs
+++ b/Assets/UniGLTF/Runtime/UniGLTF/IO/Parser/GlbBinaryParser.cs
@@ -6,8 +6,8 @@ namespace UniGLTF
     {
         private readonly byte[] _data;
         private readonly string _name;
-        
-        public GlbBinaryParser(byte[] data, string uniqueName)
+
+        public GlbBinaryParser(byte[] data, string uniqueName = "tmp")
         {
             _data = data;
 
diff --git a/Assets/VRM10/Runtime/IO/Vrm10Data.cs b/Assets/VRM10/Runtime/IO/Vrm10Data.cs
index 9ad29fcea..4e0deb9ee 100644
--- a/Assets/VRM10/Runtime/IO/Vrm10Data.cs
+++ b/Assets/VRM10/Runtime/IO/Vrm10Data.cs
@@ -68,8 +68,6 @@ namespace UniVRM10
             try
             {
                 var json = data.Json.ParseAsJson();
-                var bin = data.Chunks.First(x => x.ChunkType == GlbChunkType.BIN);
-
                 try
                 {
                     if (!json.TryGet("extensions", out JsonNode extensions))
@@ -95,7 +93,7 @@ namespace UniVRM10
                     return false;
                 }
 
-                migrated = MigrationVrm.Migrate(json, bin.Bytes);
+                migrated = MigrationVrm.Migrate(data);
                 if (migrated == null)
                 {
                     result = new Vrm10Data(default, default, Vrm10FileType.Vrm0, "vrm0: cannot migrate");
diff --git a/Assets/VRM10/Runtime/Migration/MigrationVrm.cs b/Assets/VRM10/Runtime/Migration/MigrationVrm.cs
index 5d027fa91..9f23fb099 100644
--- a/Assets/VRM10/Runtime/Migration/MigrationVrm.cs
+++ b/Assets/VRM10/Runtime/Migration/MigrationVrm.cs
@@ -12,20 +12,14 @@ namespace UniVRM10
     {
         public static byte[] Migrate(byte[] src)
         {
-            var glb = UniGLTF.Glb.Parse(src);
-            var json = glb.Json.Bytes.ParseAsJson();
-            return Migrate(json, glb.Binary.Bytes);
+            var data = new UniGLTF.GlbBinaryParser(src).Parse();
+            return Migrate(data);
         }
 
-        public static byte[] Migrate(JsonNode json, ArraySegment<byte> bin)
+        public static byte[] Migrate(UniGLTF.GltfData data)
         {
-            var gltf = UniGLTF.GltfDeserializer.Deserialize(json);
-
-            // attach glb bin to buffer
-            foreach (var buffer in gltf.buffers)
-            {
-                buffer.OpenStorage(new UniGLTF.SimpleStorage(bin));
-            }
+            var gltf = data.GLTF;
+            var json = data.Json.ParseAsJson();
 
             // https://github.com/vrm-c/vrm-specification/issues/205
             RotateY180.Rotate(gltf);
@@ -107,7 +101,7 @@ namespace UniVRM10
                 vrm1Json = f.GetStoreBytes();
             }
             // JSON 部分だけが改変されて、BIN はそのまま
-            return UniGLTF.Glb.Create(vrm1Json, bin).ToBytes();
+            return UniGLTF.Glb.Create(vrm1Json, data.Bin).ToBytes();
         }
 
         public static void Check(JsonNode vrm0, UniGLTF.Extensions.VRMC_vrm.VRMC_vrm vrm1)
@@ -121,4 +115,5 @@ namespace UniVRM10
             // Migration.CheckSpringBone(vrm0["secondaryAnimation"], vrm1.sp)
         }
     }
-}
+
+}
\ No newline at end of file