diff --git a/BizHawk.Emulation.Cores/Computers/SinclairSpectrum/ZXSpectrum.IMemoryDomains.cs b/BizHawk.Emulation.Cores/Computers/SinclairSpectrum/ZXSpectrum.IMemoryDomains.cs
index 85083f3fcc..716c29ec95 100644
--- a/BizHawk.Emulation.Cores/Computers/SinclairSpectrum/ZXSpectrum.IMemoryDomains.cs
+++ b/BizHawk.Emulation.Cores/Computers/SinclairSpectrum/ZXSpectrum.IMemoryDomains.cs
@@ -8,7 +8,7 @@ namespace BizHawk.Emulation.Cores.Computers.SinclairSpectrum
 {
     public partial class ZXSpectrum //: IMemoryDomains
     {
-        private MemoryDomainList memoryDomains;
+        internal IMemoryDomains memoryDomains;
         private readonly Dictionary<string, MemoryDomainByteArray> _byteArrayDomains = new Dictionary<string, MemoryDomainByteArray>();
         private bool _memoryDomainsInit = false;
 
@@ -42,8 +42,6 @@ namespace BizHawk.Emulation.Cores.Computers.SinclairSpectrum
             (ServiceProvider as BasicServiceProvider).Register<IMemoryDomains>(memoryDomains);
 
             _memoryDomainsInit = true;
-
-
         }
 
         private void SyncAllByteArrayDomains()
diff --git a/BizHawk.Emulation.Cores/Computers/SinclairSpectrum/ZXSpectrum.cs b/BizHawk.Emulation.Cores/Computers/SinclairSpectrum/ZXSpectrum.cs
index 3491c4a60c..b8d3749514 100644
--- a/BizHawk.Emulation.Cores/Computers/SinclairSpectrum/ZXSpectrum.cs
+++ b/BizHawk.Emulation.Cores/Computers/SinclairSpectrum/ZXSpectrum.cs
@@ -24,6 +24,7 @@ namespace BizHawk.Emulation.Cores.Computers.SinclairSpectrum
             var ser = new BasicServiceProvider(this);
             ServiceProvider = ser;    
             InputCallbacks = new InputCallbackSystem();
+            MemoryCallbacks = new MemoryCallbackSystem(new[] { "System Bus" });
 
             CoreComm = comm;