diff --git a/OpenRA.Game/Primitives/MergedStream.cs b/OpenRA.Game/Primitives/MergedStream.cs
index af0e7ac7a0..e4dd99d6ed 100644
--- a/OpenRA.Game/Primitives/MergedStream.cs
+++ b/OpenRA.Game/Primitives/MergedStream.cs
@@ -9,6 +9,7 @@
  */
 #endregion
 
+using System;
 using System.IO;
 
 namespace OpenRA.Primitives
@@ -18,7 +19,7 @@ namespace OpenRA.Primitives
 		public Stream Stream1 { get; set; }
 		public Stream Stream2 { get; set; }
 
-		long VirtualLength { get; set; }
+		long VirtualLength { get; }
 		long position;
 
 		public MergedStream(Stream stream1, Stream stream2)
@@ -61,7 +62,21 @@ namespace OpenRA.Primitives
 
 		public override void SetLength(long value)
 		{
-			VirtualLength = value;
+			throw new NotSupportedException();
+		}
+
+		public override int ReadByte()
+		{
+			int value;
+
+			if (position >= Stream1.Length)
+				value = Stream2.ReadByte();
+			else
+				value = Stream1.ReadByte();
+
+			position++;
+
+			return value;
 		}
 
 		public override int Read(byte[] buffer, int offset, int count)
@@ -83,12 +98,14 @@ namespace OpenRA.Primitives
 			return bytesRead;
 		}
 
+		public override void WriteByte(byte value)
+		{
+			throw new NotSupportedException();
+		}
+
 		public override void Write(byte[] buffer, int offset, int count)
 		{
-			if (position >= Stream1.Length)
-				Stream2.Write(buffer, offset - (int)Stream1.Length, count);
-			else
-				Stream1.Write(buffer, offset, count);
+			throw new NotSupportedException();
 		}
 
 		public override bool CanRead
@@ -103,7 +120,7 @@ namespace OpenRA.Primitives
 
 		public override bool CanWrite
 		{
-			get { return Stream1.CanWrite && Stream2.CanWrite; }
+			get { return false; }
 		}
 
 		public override long Length
diff --git a/OpenRA.Game/Primitives/ReadOnlyAdapterStream.cs b/OpenRA.Game/Primitives/ReadOnlyAdapterStream.cs
index 8b53435b8a..1001332b0c 100644
--- a/OpenRA.Game/Primitives/ReadOnlyAdapterStream.cs
+++ b/OpenRA.Game/Primitives/ReadOnlyAdapterStream.cs
@@ -48,9 +48,25 @@ namespace OpenRA.Primitives
 
 		public sealed override long Seek(long offset, SeekOrigin origin) { throw new NotSupportedException(); }
 		public sealed override void SetLength(long value) { throw new NotSupportedException(); }
+		public sealed override void WriteByte(byte value) { throw new NotSupportedException(); }
 		public sealed override void Write(byte[] buffer, int offset, int count) { throw new NotSupportedException(); }
 		public sealed override void Flush() { throw new NotSupportedException(); }
 
+		public sealed override int ReadByte()
+		{
+			if (data.Count > 0)
+				return data.Dequeue();
+
+			while (!baseStreamEmpty)
+			{
+				baseStreamEmpty = BufferData(baseStream, data);
+				if (data.Count > 0)
+					return data.Dequeue();
+			}
+
+			return -1;
+		}
+
 		public sealed override int Read(byte[] buffer, int offset, int count)
 		{
 			var copied = 0;
@@ -66,7 +82,8 @@ namespace OpenRA.Primitives
 		}
 
 		/// <summary>
-		/// Reads data into a buffer, which will be used to satisfy <see cref="Read(byte[], int, int)"/> calls.
+		/// Reads data into a buffer, which will be used to satisfy <see cref="ReadByte()"/> and
+		/// <see cref="Read(byte[], int, int)"/> calls.
 		/// </summary>
 		/// <param name="baseStream">The source stream from which bytes should be read.</param>
 		/// <param name="data">The queue where bytes should be enqueued. Do not dequeue from this buffer.</param>
diff --git a/OpenRA.Game/Primitives/SegmentStream.cs b/OpenRA.Game/Primitives/SegmentStream.cs
index 66080af01a..7b24bdba7b 100644
--- a/OpenRA.Game/Primitives/SegmentStream.cs
+++ b/OpenRA.Game/Primitives/SegmentStream.cs
@@ -59,8 +59,35 @@ namespace OpenRA.Primitives
 			set { BaseStream.Position = BaseOffset + value; }
 		}
 
-		public override int Read(byte[] buffer, int offset, int count) { return BaseStream.Read(buffer, offset, count); }
-		public override void Write(byte[] buffer, int offset, int count) { BaseStream.Write(buffer, offset, count); }
+		public override int ReadByte()
+		{
+			if (Position < Length)
+				return BaseStream.ReadByte();
+			return -1;
+		}
+
+		public override int Read(byte[] buffer, int offset, int count)
+		{
+			var remaining = Length - Position;
+			if (remaining <= 0)
+				return 0;
+			return BaseStream.Read(buffer, offset, (int)Math.Min(remaining, count));
+		}
+
+		public override void WriteByte(byte value)
+		{
+			if (Position < Length)
+				BaseStream.WriteByte(value);
+			throw new IOException("Attempted to write past the end of the stream.");
+		}
+
+		public override void Write(byte[] buffer, int offset, int count)
+		{
+			if (Position + count >= Length)
+				throw new IOException("Attempted to write past the end of the stream.");
+			BaseStream.Write(buffer, offset, count);
+		}
+
 		public override void Flush() { BaseStream.Flush(); }
 		public override long Seek(long offset, SeekOrigin origin)
 		{