diff --git a/Mono.Cecil.Cil/PortablePdb.cs b/Mono.Cecil.Cil/PortablePdb.cs
index b5515ba91..bfd31b55e 100644
--- a/Mono.Cecil.Cil/PortablePdb.cs
+++ b/Mono.Cecil.Cil/PortablePdb.cs
@@ -330,6 +330,14 @@ void CheckMethodDebugInformationTable ()
 		}
 
 		public void Dispose ()
+		{
+			if (IsEmbedded)
+				return;
+
+			writer.stream.Dispose ();
+		}
+
+		public void Write ()
 		{
 			if (IsEmbedded)
 				return;
@@ -348,7 +356,6 @@ void WritePdbFile ()
 			writer.WriteMetadata ();
 
 			writer.Flush ();
-			writer.stream.Dispose ();
 		}
 
 		void WritePdbHeap ()
@@ -425,8 +432,6 @@ public ISymbolReaderProvider GetReaderProvider ()
 
 		public ImageDebugHeader GetDebugHeader ()
 		{
-			writer.Dispose ();
-
 			var directory = new ImageDebugDirectory {
 				Type = ImageDebugType.EmbeddedPortablePdb,
 				MajorVersion = 0x0100,
@@ -450,10 +455,12 @@ public ImageDebugHeader GetDebugHeader ()
 
 			directory.SizeOfData = (int) data.Length;
 
-			return new ImageDebugHeader (new [] {
-				writer.GetDebugHeader ().Entries [0],
-				new ImageDebugHeaderEntry (directory, data.ToArray ())
-			});
+			var header = writer.GetDebugHeader ();
+			var entries = new ImageDebugHeaderEntry [header.Entries.Length + 1];
+			Array.Copy (header.Entries, 0, entries, 0, header.Entries.Length);
+			entries [entries.Length - 1] = new ImageDebugHeaderEntry (directory, data.ToArray ());
+
+			return new ImageDebugHeader (entries);
 		}
 
 		public void Write (MethodDebugInformation info)
@@ -461,8 +468,14 @@ public void Write (MethodDebugInformation info)
 			writer.Write (info);
 		}
 
+		public void Write ()
+		{
+			writer.Write ();
+		}
+
 		public void Dispose ()
 		{
+			writer.Dispose ();
 		}
 	}
 
diff --git a/Mono.Cecil.Cil/Symbols.cs b/Mono.Cecil.Cil/Symbols.cs
index f1f85a0a6..535bc6022 100644
--- a/Mono.Cecil.Cil/Symbols.cs
+++ b/Mono.Cecil.Cil/Symbols.cs
@@ -38,6 +38,7 @@ public enum ImageDebugType {
 		CodeView = 2,
 		Deterministic = 16,
 		EmbeddedPortablePdb = 17,
+		PdbChecksum = 19,
 	}
 
 	public sealed class ImageDebugHeader {
@@ -1015,6 +1016,7 @@ public interface ISymbolWriter : IDisposable {
 		ISymbolReaderProvider GetReaderProvider ();
 		ImageDebugHeader GetDebugHeader ();
 		void Write (MethodDebugInformation info);
+		void Write ();
 	}
 
 	public interface ISymbolWriterProvider {
diff --git a/Mono.Cecil/AssemblyWriter.cs b/Mono.Cecil/AssemblyWriter.cs
index 3ea1088b3..4ab94a8d5 100644
--- a/Mono.Cecil/AssemblyWriter.cs
+++ b/Mono.Cecil/AssemblyWriter.cs
@@ -121,6 +121,9 @@ static void Write (ModuleDefinition module, Disposable<Stream> stream, WriterPar
 					if (parameters.DeterministicMvid)
 						metadata.ComputeDeterministicMvid ();
 
+					if (symbol_writer != null)
+						symbol_writer.Write ();
+
 					var writer = ImageWriter.CreateWriter (module, metadata, stream);
 					stream.value.SetLength (0);
 					writer.WriteImage ();
diff --git a/Test/Mono.Cecil.Tests/PortablePdbTests.cs b/Test/Mono.Cecil.Tests/PortablePdbTests.cs
index 6e1efbc90..3b538ec74 100644
--- a/Test/Mono.Cecil.Tests/PortablePdbTests.cs
+++ b/Test/Mono.Cecil.Tests/PortablePdbTests.cs
@@ -632,6 +632,11 @@ public void Write (MethodDebugInformation info)
 				symbol_writer.Write (info);
 			}
 
+			public void Write ()
+			{
+				symbol_writer.Write ();
+			}
+
 			public void Dispose ()
 			{
 				symbol_writer.Dispose ();
diff --git a/symbols/mdb/Mono.Cecil.Mdb/MdbWriter.cs b/symbols/mdb/Mono.Cecil.Mdb/MdbWriter.cs
index becbb4f88..8f34d95eb 100644
--- a/symbols/mdb/Mono.Cecil.Mdb/MdbWriter.cs
+++ b/symbols/mdb/Mono.Cecil.Mdb/MdbWriter.cs
@@ -167,11 +167,15 @@ public ImageDebugHeader GetDebugHeader ()
 			return new ImageDebugHeader ();
 		}
 
-		public void Dispose ()
+		public void Write ()
 		{
 			writer.WriteSymbolFile (mvid);
 		}
 
+		public void Dispose ()
+		{
+		}
+
 		class SourceFile : ISourceFile {
 
 			readonly CompileUnitEntry compilation_unit;
diff --git a/symbols/pdb/Mono.Cecil.Pdb/NativePdbWriter.cs b/symbols/pdb/Mono.Cecil.Pdb/NativePdbWriter.cs
index 01b6c7a51..2e560a9f2 100644
--- a/symbols/pdb/Mono.Cecil.Pdb/NativePdbWriter.cs
+++ b/symbols/pdb/Mono.Cecil.Pdb/NativePdbWriter.cs
@@ -28,6 +28,9 @@ public class NativePdbWriter : ISymbolWriter {
 		readonly Dictionary<string, SymDocumentWriter> documents;
 		readonly Dictionary<ImportDebugInformation, MetadataToken> import_info_to_parent;
 
+		ImageDebugDirectory debug_directory;
+		byte [] debug_info;
+
 		internal NativePdbWriter (ModuleDefinition module, SymWriter writer)
 		{
 			this.module = module;
@@ -44,10 +47,7 @@ public ISymbolReaderProvider GetReaderProvider ()
 
 		public ImageDebugHeader GetDebugHeader ()
 		{
-			ImageDebugDirectory directory;
-			var data = writer.GetDebugInfo (out directory);
-			directory.TimeDateStamp = (int) module.timestamp;
-			return new ImageDebugHeader (new ImageDebugHeaderEntry (directory, data));
+			return new ImageDebugHeader (new ImageDebugHeaderEntry (debug_directory, debug_info));
 		}
 
 		public void Write (MethodDebugInformation info)
@@ -253,14 +253,21 @@ SymDocumentWriter GetDocument (Document document)
 			return doc_writer;
 		}
 
-		public void Dispose ()
+		public void Write ()
 		{
 			var entry_point = module.EntryPoint;
 			if (entry_point != null)
 				writer.SetUserEntryPoint (entry_point.MetadataToken.ToInt32 ());
 
+			debug_info = writer.GetDebugInfo (out debug_directory);
+			debug_directory.TimeDateStamp = (int) module.timestamp;
+
 			writer.Close ();
 		}
+
+		public void Dispose ()
+		{
+		}
 	}
 
 	enum CustomMetadataType : byte {