diff --git a/ArcFormats/ArcISA.cs b/ArcFormats/ArcISA.cs
index ca2d748e..86f44f7b 100644
--- a/ArcFormats/ArcISA.cs
+++ b/ArcFormats/ArcISA.cs
@@ -2,7 +2,7 @@
 //! \date       Tue Mar 17 09:21:03 2015
 //! \brief      ISM engine resource archive.
 //
-// Copyright (C) 2015 by morkt
+// Copyright (C) 2015-2018 by morkt
 //
 // Permission is hereby granted, free of charge, to any person obtaining a copy
 // of this software and associated documentation files (the "Software"), to
@@ -47,23 +47,50 @@ namespace GameRes.Formats.ISM
             int version = file.View.ReadUInt16 (0x0E);
             bool is_encrypted = (version & 0x8000) != 0;
             version &= 0x7FFF;
+            var reader = new IsaIndexReader (file, count);
+            List<Entry> dir = null;
+            if (version != 1)
+                dir = reader.ReadIndex (0x0C, 0x14);
+            if (null == dir)
+                dir = reader.ReadIndex (0x30, 0x10);
+            if (null == dir)
+                return null;
+            return new ArcFile (file, this, dir);
+        }
+    }
+
+    internal class IsaIndexReader
+    {
+        ArcView     m_file;
+        List<Entry> m_dir;
+        int         m_count;
+
+        public IsaIndexReader (ArcView file, int count)
+        {
+            m_file = file;
+            m_dir = new List<Entry> (count);
+            m_count = count;
+        }
+
+        public List<Entry> ReadIndex (uint name_length, uint record_length)
+        {
+            m_dir.Clear();
             uint index_offset = 0x10;
-            uint name_length   = 1 == version ? 0x30u : 0x0Cu;
-            uint record_length = 1 == version ? 0x10u : 0x14u;
-            var dir = new List<Entry> (count);
-            for (int i = 0; i < count; ++i)
+            for (int i = 0; i < m_count; ++i)
             {
-                var name = file.View.ReadString (index_offset, name_length);
+                var name = m_file.View.ReadString (index_offset, name_length);
+                if (0 == name.Length)
+                    return null;
                 var entry = FormatCatalog.Instance.Create<Entry> (name);
                 index_offset += name_length;
-                entry.Offset = file.View.ReadUInt32 (index_offset+4);
-                entry.Size = file.View.ReadUInt32 (index_offset+8);
-                if (!entry.CheckPlacement (file.MaxOffset))
+                entry.Offset = m_file.View.ReadUInt32 (index_offset+4);
+                entry.Size = m_file.View.ReadUInt32 (index_offset+8);
+                if (!entry.CheckPlacement (m_file.MaxOffset))
                     return null;
-                dir.Add (entry);
+                m_dir.Add (entry);
                 index_offset += record_length;
             }
-            return new ArcFile (file, this, dir);
+            return m_dir;
         }
 
         unsafe void DecryptIndex (byte[] data)