diff --git a/KaitaiStream.cs b/KaitaiStream.cs
index c1d6b22..d7464ef 100644
--- a/KaitaiStream.cs
+++ b/KaitaiStream.cs
@@ -2,7 +2,6 @@ using System;
 using System.Collections.Generic;
 using System.IO;
 using System.IO.Compression;
-using System.Linq;
 using System.Globalization;
 
 namespace Kaitai
@@ -615,7 +614,8 @@ namespace Kaitai
                 {
                     using (MemoryStream target = new MemoryStream())
                     {
-                        ds.CopyTo(target);
+                        byte[] buffer = new byte[32768];
+                        CopyTo(target, ds);
                         return target.ToArray();
                     }
                 }
@@ -708,5 +708,24 @@ namespace Kaitai
         }
 
         #endregion
+
+        #region Compatibility methods
+
+        /// <summary>
+        /// Replaces Stream.CopyTo from System.Linq for backwards compatibility.
+        /// </summary>
+        /// <param name="source">Stream to copy data from.</param>
+        /// <param name="destination">Stream to copy data to.</param>
+        private static void CopyTo(Stream source, Stream destination)
+        {
+            byte[] buffer = new byte[32768];
+            int read;
+            while ((read = source.Read(buffer, 0, buffer.Length)) > 0)
+            {
+                destination.Write(buffer, 0, read);
+            }
+        }
+
+        #endregion
     }
 }