diff --git a/OpenRA.FileFormats/Filesystem/ZipFile.cs b/OpenRA.FileFormats/Filesystem/ZipFile.cs
index d7830ecd40..0cd43ecbee 100644
--- a/OpenRA.FileFormats/Filesystem/ZipFile.cs
+++ b/OpenRA.FileFormats/Filesystem/ZipFile.cs
@@ -46,7 +46,15 @@ namespace OpenRA.FileFormats
 
 		public Stream GetContent(string filename)
 		{
-			return pkg.GetInputStream(pkg.GetEntry(filename));
+			var ms = new MemoryStream();
+			var z = pkg.GetInputStream(pkg.GetEntry(filename));
+			int bufSize = 2048;
+			byte[] buf = new byte[bufSize];
+			while ((bufSize = z.Read(buf, 0, buf.Length)) > 0)
+				ms.Write(buf, 0, bufSize);
+			
+			ms.Seek(0, SeekOrigin.Begin);
+			return ms;
 		}
 
 		public IEnumerable<uint> AllFileHashes()
diff --git a/OpenRA.Game/Game.cs b/OpenRA.Game/Game.cs
index 24368d1824..aabc0c044b 100755
--- a/OpenRA.Game/Game.cs
+++ b/OpenRA.Game/Game.cs
@@ -251,9 +251,13 @@ namespace OpenRA
 
         static string ChooseShellmap()
         {
-            return modData.AvailableMaps
-                .Where(m => m.Value.UseAsShellmap)
-                .Random(CosmeticRandom).Key;
+            var shellmaps =  modData.AvailableMaps
+                .Where(m => m.Value.UseAsShellmap);
+			
+			if (shellmaps.Count() == 0)
+				throw new InvalidDataException("No valid shellmaps available");
+			
+			return shellmaps.Random(CosmeticRandom).Key;
         }
 
 		static bool quit;
diff --git a/OpenRA.Game/Map.cs b/OpenRA.Game/Map.cs
index 67dfba2d20..55d9473932 100644
--- a/OpenRA.Game/Map.cs
+++ b/OpenRA.Game/Map.cs
@@ -195,11 +195,12 @@ namespace OpenRA
 
 		public void Save(string toPath)
 		{			
+			Console.WriteLine("Saving map to path {0}",toPath);
 			// Todo: save to a zip file in the support dir by default
 			MapFormat = 3;
 			
 			var root = new List<MiniYamlNode>();
-			foreach (var field in new string[] {"Selectable", "MapFormat", "Title", "Description", "Author", "PlayerCount", "Tileset", "MapSize", "TopLeft", "BottomRight"})
+			foreach (var field in new string[] {"Selectable", "MapFormat", "Title", "Description", "Author", "PlayerCount", "Tileset", "MapSize", "TopLeft", "BottomRight", "UseAsShellmap"})
 			{
 				FieldInfo f = this.GetType().GetField(field);
 				if (f.GetValue(this) == null) continue;
diff --git a/OpenRA.Game/ModData.cs b/OpenRA.Game/ModData.cs
index 88a0d01e74..1a3c9a0d87 100755
--- a/OpenRA.Game/ModData.cs
+++ b/OpenRA.Game/ModData.cs
@@ -62,8 +62,16 @@ namespace OpenRA
 		{
             var paths = mods.SelectMany(p => FindMapsIn("mods/" + p + "/maps/"));
 
-			return paths.Select(p => new MapStub(p))
-                .ToDictionary(m => m.Uid);
+			Dictionary<string, MapStub> ret = new Dictionary<string, MapStub>();
+			foreach (var path in paths)
+			{
+				var map = new MapStub(path);
+				if (ret.ContainsKey(map.Uid))
+					System.Console.WriteLine("Ignoring duplicate map: {0}", path);
+				else
+					ret.Add(map.Uid, map);
+			}
+			return ret;
 		}
 		
 		string cachedTileset = null;