diff --git a/BizHawk.Emulation.Cores/Waterbox/ElfRunner.cs b/BizHawk.Emulation.Cores/Waterbox/ElfRunner.cs
index 0a27e2f67f..dcca1d1d30 100644
--- a/BizHawk.Emulation.Cores/Waterbox/ElfRunner.cs
+++ b/BizHawk.Emulation.Cores/Waterbox/ElfRunner.cs
@@ -16,7 +16,7 @@ using BizHawk.Emulation.Common;
 
 namespace BizHawk.Emulation.Cores.Waterbox
 {
-	public sealed class ElfRunner : Swappable, IImportResolver, IBinaryStateable, IDisposable
+	public sealed class ElfRunner : Swappable, IImportResolver, IBinaryStateable
 	{
 		// TODO: a lot of things only work with our elves and aren't fully generalized
 
@@ -265,13 +265,6 @@ namespace BizHawk.Emulation.Cores.Waterbox
 			_symlist = symbols.ToList();
 		}
 
-		public void Dispose()
-		{
-			// we don't need to activate to dispose
-			Dispose(true);
-			//GC.SuppressFinalize(this);
-		}
-
 		public void Seal()
 		{
 			Enter();
@@ -285,13 +278,9 @@ namespace BizHawk.Emulation.Cores.Waterbox
 			}
 		}
 
-		//~ElfRunner()
-		//{
-		//	Dispose(false);
-		//}
-
-		private void Dispose(bool disposing)
+		protected override void Dispose(bool disposing)
 		{
+			base.Dispose(disposing);
 			if (disposing)
 			{
 				foreach (var d in _disposeList)
@@ -305,7 +294,6 @@ namespace BizHawk.Emulation.Cores.Waterbox
 			}
 		}
 
-
 		#region clib monkeypatches
 
 		// our clib expects a few function pointers to be defined for it
diff --git a/BizHawk.Emulation.Cores/Waterbox/Heap.cs b/BizHawk.Emulation.Cores/Waterbox/Heap.cs
index cb73c3a751..f62cd778e1 100644
--- a/BizHawk.Emulation.Cores/Waterbox/Heap.cs
+++ b/BizHawk.Emulation.Cores/Waterbox/Heap.cs
@@ -34,6 +34,7 @@ namespace BizHawk.Emulation.Cores.Waterbox
 			Memory = new MemoryBlock(start, size);
 			Used = 0;
 			Name = name;
+			Console.WriteLine("Created heap `{1}` at {0:x16}:{2:x16}", start, name, start + size);
 		}
 
 		private void EnsureAlignment(int align)
@@ -118,7 +119,7 @@ namespace BizHawk.Emulation.Cores.Waterbox
 				var hash = br.ReadBytes(_hash.Length);
 				if (!hash.SequenceEqual(_hash))
 				{
-					throw new InvalidOperationException(string.Format("Hash did not match for heap {0}.  Is this the same rom?"));
+					throw new InvalidOperationException(string.Format("Hash did not match for heap {0}.  Is this the same rom?", Name));
 				}
 			}
 		}
diff --git a/BizHawk.Emulation.Cores/Waterbox/PeRunner.cs b/BizHawk.Emulation.Cores/Waterbox/PeRunner.cs
index 1d3180a2fc..964b4552a9 100644
--- a/BizHawk.Emulation.Cores/Waterbox/PeRunner.cs
+++ b/BizHawk.Emulation.Cores/Waterbox/PeRunner.cs
@@ -57,7 +57,7 @@ namespace BizHawk.Emulation.Cores.Waterbox
 				entryThunk();
 			}
 
-			public PeWrapper(string moduleName, byte[] fileData)
+			public PeWrapper(string moduleName, byte[] fileData, ulong destAddress)
 			{
 				ModuleName = moduleName;
 				_fileData = fileData;
@@ -70,12 +70,13 @@ namespace BizHawk.Emulation.Cores.Waterbox
 				}
 
 				_fileHash = WaterboxUtils.Hash(fileData);
+				Mount(destAddress);
 			}
 
 			/// <summary>
-			/// set memory protections, finishing the Mount process
+			/// set memory protections.
 			/// </summary>
-			public void FinishMount()
+			private void ProtectMemory()
 			{
 				Memory.Protect(Memory.Start, Memory.Size, MemoryBlock.Protection.R);
 
@@ -103,7 +104,7 @@ namespace BizHawk.Emulation.Cores.Waterbox
 			/// load the PE into memory
 			/// </summary>
 			/// <param name="org">start address</param>
-			public void Mount(ulong org)
+			private void Mount(ulong org)
 			{
 				Start = org;
 				LoadOffset = (long)Start - (long)_pe.ImageNtHeaders.OptionalHeader.ImageBase;
@@ -159,6 +160,7 @@ namespace BizHawk.Emulation.Cores.Waterbox
 						}
 					}
 				}
+				ProtectMemory();
 
 				// publish exports
 				EntryPoint = Z.US(Start + _pe.ImageNtHeaders.OptionalHeader.AddressOfEntryPoint);
@@ -263,7 +265,7 @@ namespace BizHawk.Emulation.Cores.Waterbox
 					WaterboxUtils.CopySome(br.BaseStream, ms, (long)length);
 				}
 
-				FinishMount();
+				ProtectMemory();
 			}
 		}
 
@@ -507,6 +509,11 @@ namespace BizHawk.Emulation.Cores.Waterbox
 		private Emu _emu;
 		private Syscalls _syscalls;
 
+		/// <summary>
+		/// timestamp of creation acts as a sort of "object id" in the savestate
+		/// </summary>
+		private readonly long _createstamp = WaterboxUtils.Timestamp();
+
 		public PeRunner(string directory, string filename, ulong heapsize, ulong sealedheapsize, ulong invisibleheapsize)
 		{
 			Initialize(_nextStart);
@@ -530,8 +537,7 @@ namespace BizHawk.Emulation.Cores.Waterbox
 					var moduleName = todoModules.Dequeue();
 					if (!_exports.ContainsKey(moduleName))
 					{
-						var module = new PeWrapper(moduleName, File.ReadAllBytes(Path.Combine(directory, moduleName)));
-						module.Mount(_nextStart);
+						var module = new PeWrapper(moduleName, File.ReadAllBytes(Path.Combine(directory, moduleName)), _nextStart);
 						ComputeNextStart(module.Size);
 						AddMemoryBlock(module.Memory);
 						_savestateComponents.Add(module);
@@ -546,17 +552,7 @@ namespace BizHawk.Emulation.Cores.Waterbox
 					}
 				}
 
-				foreach (var module in _modules)
-				{
-					foreach (var name in module.ImportsByModule.Keys)
-					{
-						module.ConnectImports(name, _exports[name]);
-					}
-				}
-				foreach (var module in _modules)
-				{
-					module.FinishMount();
-				}
+				ConnectAllImports();
 
 				// load all heaps
 				_heap = new Heap(_nextStart, heapsize, "brk-heap");
@@ -618,11 +614,23 @@ namespace BizHawk.Emulation.Cores.Waterbox
 			}
 		}
 
+		private void ConnectAllImports()
+		{
+			foreach (var module in _modules)
+			{
+				foreach (var name in module.ImportsByModule.Keys)
+				{
+					module.ConnectImports(name, _exports[name]);
+				}
+			}
+		}
+
 		public void SaveStateBinary(BinaryWriter bw)
 		{
+			bw.Write(_createstamp);
+			bw.Write(_savestateComponents.Count);
 			using (this.EnterExit())
 			{
-				bw.Write(_savestateComponents.Count);
 				foreach (var c in _savestateComponents)
 				{
 					c.SaveStateBinary(bw);
@@ -632,6 +640,7 @@ namespace BizHawk.Emulation.Cores.Waterbox
 
 		public void LoadStateBinary(BinaryReader br)
 		{
+			var differentCore = br.ReadInt64() != _createstamp; // true if a different core instance created the state
 			if (br.ReadInt32() != _savestateComponents.Count)
 				throw new InvalidOperationException("Internal savestate error");
 			using (this.EnterExit())
@@ -640,14 +649,20 @@ namespace BizHawk.Emulation.Cores.Waterbox
 				{
 					c.LoadStateBinary(br);
 				}
+				if (differentCore)
+				{
+					// if a different runtime instance than this one saved the state,
+					// Exvoker imports need to be reconnected
+					Console.WriteLine("Restoring PeRunner state from a different core...");
+					ConnectAllImports();
+				}
 			}
 		}
 
-		private bool _disposed = false;
-
-		public void Dispose()
+		protected override void Dispose(bool disposing)
 		{
-			if (!_disposed)
+			base.Dispose(disposing);
+			if (disposing)
 			{
 				foreach (var d in _disposeList)
 					d.Dispose();
@@ -658,7 +673,6 @@ namespace BizHawk.Emulation.Cores.Waterbox
 				_heap = null;
 				_sealedheap = null;
 				_invisibleheap = null;
-				_disposed = true;
 			}
 		}
 	}
diff --git a/BizHawk.Emulation.Cores/Waterbox/Swappable.cs b/BizHawk.Emulation.Cores/Waterbox/Swappable.cs
index d6046dbb31..dfa5e484b8 100644
--- a/BizHawk.Emulation.Cores/Waterbox/Swappable.cs
+++ b/BizHawk.Emulation.Cores/Waterbox/Swappable.cs
@@ -12,13 +12,18 @@ namespace BizHawk.Emulation.Cores.Waterbox
 	/// represents an object that can be swapped in and out of memory to compete with other objects in the same memory
 	/// not suited for general purpose stuff
 	/// </summary>
-	public abstract class Swappable : IMonitor
+	public abstract class Swappable : IMonitor, IDisposable
 	{
 		/// <summary>
 		/// start address, or 0 if we don't need to be swapped
 		/// </summary>
 		private ulong _lockkey = 0;
 
+		/// <summary>
+		/// the the relevant lockinfo for this core
+		/// </summary>
+		private LockInfo _currentLockInfo;
+
 		/// <summary>
 		/// everything to swap in for context switches
 		/// </summary>
@@ -37,6 +42,10 @@ namespace BizHawk.Emulation.Cores.Waterbox
 		protected void Initialize(ulong lockkey)
 		{
 			_lockkey = lockkey;
+			if (lockkey != 0)
+			{
+				_currentLockInfo = LockInfos.GetOrAdd(_lockkey, new LockInfo { Sync = new object() });
+			}
 		}
 
 		/// <summary>
@@ -50,30 +59,38 @@ namespace BizHawk.Emulation.Cores.Waterbox
 		private class LockInfo
 		{
 			public object Sync;
-			public Swappable Loaded;
+			private WeakReference LoadedRef = new WeakReference(null);
+			public Swappable Loaded
+			{
+				get
+				{
+					// if somehow an object died without being disposed,
+					// the MemoryBlock finalizer will have unloaded the memory
+					// and so we can treat it as if no Swappable was attached
+					return (Swappable)LoadedRef.Target;
+				}
+				set
+				{
+					LoadedRef.Target = value;
+				}
+			}
 		}
 
 		private static readonly ConcurrentDictionary<ulong, LockInfo> LockInfos = new ConcurrentDictionary<ulong, LockInfo>();
 
-		static Swappable()
-		{
-			LockInfos.GetOrAdd(0, new LockInfo()); // any errant attempt to lock when ShouldMonitor == false will result in NRE
-		}
-
 		/// <summary>
 		/// acquire lock and swap this into memory
 		/// </summary>
 		public void Enter()
 		{
-			var li = LockInfos.GetOrAdd(_lockkey, new LockInfo { Sync = new object() });
-			Monitor.Enter(li.Sync);
-			if (li.Loaded != this)
+			Monitor.Enter(_currentLockInfo.Sync);
+			if (_currentLockInfo.Loaded != this)
 			{
-				if (li.Loaded != null)
-					li.Loaded.DeactivateInternal();
-				li.Loaded = null;
+				if (_currentLockInfo.Loaded != null)
+					_currentLockInfo.Loaded.DeactivateInternal();
+				_currentLockInfo.Loaded = null;
 				ActivateInternal();
-				li.Loaded = this;
+				_currentLockInfo.Loaded = this;
 			}
 		}
 
@@ -82,8 +99,7 @@ namespace BizHawk.Emulation.Cores.Waterbox
 		/// </summary>
 		public void Exit()
 		{
-			var li = LockInfos.GetOrAdd(_lockkey, new LockInfo { Sync = new object() });
-			Monitor.Exit(li.Sync);
+			Monitor.Exit(_currentLockInfo.Sync);
 		}
 
 		private void DeactivateInternal()
@@ -100,5 +116,31 @@ namespace BizHawk.Emulation.Cores.Waterbox
 				m.Activate();
 		}
 
+		private bool _disposed = false;
+
+		protected virtual void Dispose(bool disposing)
+		{
+			if (!_disposed)
+			{
+				if (disposing)
+				{
+					lock (_currentLockInfo.Sync)
+					{
+						if (_currentLockInfo.Loaded == this)
+						{
+							DeactivateInternal();
+							_currentLockInfo.Loaded = null;
+						}
+						_currentLockInfo = null;
+					}
+				}
+				_disposed = true;
+			}
+		}
+
+		public void Dispose()
+		{
+			Dispose(true);
+		}
 	}
 }
diff --git a/BizHawk.Emulation.Cores/Waterbox/WaterboxUtils.cs b/BizHawk.Emulation.Cores/Waterbox/WaterboxUtils.cs
index 9b01f29da2..db93aa3b64 100644
--- a/BizHawk.Emulation.Cores/Waterbox/WaterboxUtils.cs
+++ b/BizHawk.Emulation.Cores/Waterbox/WaterboxUtils.cs
@@ -51,5 +51,10 @@ namespace BizHawk.Emulation.Cores.Waterbox
 				*p++ = 0;
 			}
 		}
+
+		public static long Timestamp()
+		{
+			return DateTime.UtcNow.Ticks;
+		}
 	}
 }