diff --git a/BizHawk.Client.EmuHawk/tools/Debugger/GenericDebugger.Disassembler.cs b/BizHawk.Client.EmuHawk/tools/Debugger/GenericDebugger.Disassembler.cs
index 1e77d978b3..9617500bd7 100644
--- a/BizHawk.Client.EmuHawk/tools/Debugger/GenericDebugger.Disassembler.cs
+++ b/BizHawk.Client.EmuHawk/tools/Debugger/GenericDebugger.Disassembler.cs
@@ -37,7 +37,10 @@ namespace BizHawk.Client.EmuHawk
 
 		public void UpdatePC()
 		{
-			currentDisassemblerAddress = (uint)PCRegister.Value;
+			if (CanDisassemble)
+			{
+				currentDisassemblerAddress = (uint)PCRegister.Value;
+			}
 		}
 
 		private void UpdateDisassembler()
diff --git a/BizHawk.Client.EmuHawk/tools/Debugger/GenericDebugger.IToolForm.cs b/BizHawk.Client.EmuHawk/tools/Debugger/GenericDebugger.IToolForm.cs
index 2344f2f5b9..c43ea2c392 100644
--- a/BizHawk.Client.EmuHawk/tools/Debugger/GenericDebugger.IToolForm.cs
+++ b/BizHawk.Client.EmuHawk/tools/Debugger/GenericDebugger.IToolForm.cs
@@ -28,6 +28,7 @@ namespace BizHawk.Client.EmuHawk
 
 		#region Implementation checking
 
+		// TODO: be cachey with checks that depend on catching exceptions
 		private bool CanUseMemoryCallbacks
 		{
 			get