diff --git a/Plugins/UniversalEditor.Plugins.Merscom/DataFormats/FileSystem/DPK/DPKDataFormat.cs b/Plugins/UniversalEditor.Plugins.Merscom/DataFormats/FileSystem/DPK/DPKDataFormat.cs
index 4871037d..2c916c09 100644
--- a/Plugins/UniversalEditor.Plugins.Merscom/DataFormats/FileSystem/DPK/DPKDataFormat.cs
+++ b/Plugins/UniversalEditor.Plugins.Merscom/DataFormats/FileSystem/DPK/DPKDataFormat.cs
@@ -20,6 +20,8 @@
 //  along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 using System;
+
+using MBS.Framework;
 using UniversalEditor.IO;
 using UniversalEditor.ObjectModels.FileSystem;
 
@@ -48,6 +50,8 @@ namespace UniversalEditor.Plugins.Merscom.DataFormats.FileSystem.DPK
 			if (fsom == null)
 				throw new ObjectModelNotSupportedException();
 
+			fsom.AdditionalDetails.Add("compressedSize", "Compressed size");
+
 			Reader br = base.Accessor.Reader;
 
 			string DPK4 = br.ReadFixedLengthString(4);
@@ -59,7 +63,7 @@ namespace UniversalEditor.Plugins.Merscom.DataFormats.FileSystem.DPK
 			uint u3 = br.ReadUInt32();
 			for (int i = 0; i < u3; i++)
 			{
-				uint u4 = br.ReadUInt32();
+				uint recordSize = br.ReadUInt32(); // size of file TOC record
 				uint decompressedLength = br.ReadUInt32();
 				uint compressedLength = br.ReadUInt32();									// 371				39325
 				uint offset = br.ReadUInt32();									// 292196			292567
@@ -71,6 +75,8 @@ namespace UniversalEditor.Plugins.Merscom.DataFormats.FileSystem.DPK
 
 				file.Properties["compressedLength"] = compressedLength;
 				file.Properties["offset"] = offset;
+				file.Properties["reader"] = Accessor.Reader;
+				file.SetAdditionalDetail("compressedSize", compressedLength);
 
 				file.Size = decompressedLength;
 
@@ -78,22 +84,112 @@ namespace UniversalEditor.Plugins.Merscom.DataFormats.FileSystem.DPK
 			}
 		}
 
+		private Guid KnownSettingsGuids_EnableLogging = new Guid("{39e459e8-e8be-4836-8274-fd1c26d498cf}");
+
+		private Compression.CompressionModule zlib { get; } = Compression.CompressionModule.FromKnownCompressionMethod(Compression.CompressionMethod.Zlib);
+
 		void File_DataRequest(object sender, DataRequestEventArgs e)
 		{
 			File file = (File)sender;
+
 			uint compressedLength = (uint)file.Properties["compressedLength"];
 			uint offset = (uint)file.Properties["offset"];
+			Reader reader = (Reader)file.Properties["reader"];
 
-			Accessor.Reader.Seek(offset, SeekOrigin.Begin);
-			byte[] compressedData = Accessor.Reader.ReadBytes(compressedLength);
-			byte[] decompressedData = Compression.CompressionModule.FromKnownCompressionMethod(Compression.CompressionMethod.Zlib).Decompress(compressedData);
-			e.Data = decompressedData;
+			if (Application.Instance.GetSetting<bool>(KnownSettingsGuids_EnableLogging))
+			{
+				Console.WriteLine(String.Format("ue: merscom: dpk: unpacking '{0}' (at {1}, compressed size {2}, decompressed size {3})", file.Name, offset, compressedLength, file.Size));
+			}
+
+			reader.Seek(offset, SeekOrigin.Begin);
+			byte[] compressedData = reader.ReadBytes(compressedLength);
+
+			if (compressedLength == file.Size)
+			{
+				// file is not compressed!
+				e.Data = compressedData;
+			}
+			else
+			{
+				byte[] decompressedData = zlib.Decompress(compressedData);
+				e.Data = decompressedData;
+			}
 		}
 
 
 		protected override void SaveInternal(ObjectModel objectModel)
 		{
-			throw new NotImplementedException();
+			FileSystemObjectModel fsom = (objectModel as FileSystemObjectModel);
+			if (fsom == null)
+				throw new ObjectModelNotSupportedException();
+
+			Writer bw = base.Accessor.Writer;
+
+			bw.WriteFixedLengthString("DPK4");
+
+			File[] files = fsom.GetAllFiles();
+			uint archiveLength = (uint)(16 + (16 * files.Length));
+			uint tocLength = (uint)(16 * files.Length);
+			for (int i = 0; i < files.Length; i++)
+			{
+				tocLength += (uint) (files[i].Name.Length + 1).Align(4);
+			}
+
+			long archiveLengthOffset = bw.Accessor.Position;
+			bw.WriteUInt32(archiveLength);
+
+			bw.WriteUInt32(tocLength);
+			bw.WriteUInt32((uint)files.Length);
+
+			uint[] offsets = new uint[files.Length];
+			uint[] compressedLengths = new uint[files.Length];
+
+			long tocOffset = bw.Accessor.Position;
+			bw.Accessor.Seek(tocLength, SeekOrigin.Current); // skip over TOC for now, will come back and write it later
+
+			uint offset = (uint)(tocOffset + tocLength);
+			offsets[0] = offset;
+			for (int i = 0; i < files.Length; i++)
+			{
+				byte[] decompressedData = files[i].GetData();
+				byte[] compressedData = zlib.Compress(decompressedData);
+				if (compressedData.Length >= decompressedData.Length)
+				{
+					// no point in using the zlib
+					bw.WriteBytes(decompressedData);
+					offset += (uint)decompressedData.Length;
+					compressedLengths[i] = (uint)decompressedData.Length;
+				}
+				else
+				{
+					bw.WriteBytes(compressedData);
+					offset += (uint)compressedData.Length;
+					compressedLengths[i] = (uint)compressedData.Length;
+				}
+
+				if (i < files.Length - 1)
+				{
+					offsets[i + 1] = offset;
+				}
+			}
+
+			// now we can write the TOC
+			bw.Accessor.Seek(tocOffset, SeekOrigin.Begin);
+			for (int i = 0; i < files.Length; i++)
+			{
+				uint recordSize = (uint)(12 + (files[i].Name.Length + 1).Align(4));
+				bw.WriteUInt32(recordSize);
+
+				uint decompressedLength = (uint)files[i].Size;
+				bw.WriteUInt32(decompressedLength);
+				bw.WriteUInt32(compressedLengths[i]);
+				bw.WriteUInt32(offsets[i]);
+				bw.WriteNullTerminatedString(files[i].Name);
+				bw.Align(4);
+			}
+
+			bw.Accessor.Seek(archiveLengthOffset, SeekOrigin.Begin);
+			bw.WriteUInt32((uint)bw.Accessor.Length);
 		}
 	}
 }
diff --git a/Plugins/UniversalEditor.Plugins.Merscom/UniversalEditor.Plugins.Merscom.csproj b/Plugins/UniversalEditor.Plugins.Merscom/UniversalEditor.Plugins.Merscom.csproj
index b16ea645..eb008b46 100644
--- a/Plugins/UniversalEditor.Plugins.Merscom/UniversalEditor.Plugins.Merscom.csproj
+++ b/Plugins/UniversalEditor.Plugins.Merscom/UniversalEditor.Plugins.Merscom.csproj
@@ -61,6 +61,10 @@
       <Project>{2D4737E6-6D95-408A-90DB-8DFF38147E85}</Project>
       <Name>UniversalEditor.Core</Name>
     </ProjectReference>
+    <ProjectReference Include="..\..\..\MBS.Framework\MBS.Framework\MBS.Framework.csproj">
+      <Project>{00266B21-35C9-4A7F-A6BA-D54D7FDCC25C}</Project>
+      <Name>MBS.Framework</Name>
+    </ProjectReference>
   </ItemGroup>
   <Import Project="$(MSBuildBinPath)\Microsoft.CSharp.targets" />
 </Project>