diff --git a/BizHawk.Emulation.Cores/Consoles/Nintendo/N64/N64.IDisassemblable.cs b/BizHawk.Emulation.Cores/Consoles/Nintendo/N64/N64.IDisassemblable.cs
index 64ae7bc911..bf1248d56f 100644
--- a/BizHawk.Emulation.Cores/Consoles/Nintendo/N64/N64.IDisassemblable.cs
+++ b/BizHawk.Emulation.Cores/Consoles/Nintendo/N64/N64.IDisassemblable.cs
@@ -30,10 +30,11 @@ namespace BizHawk.Emulation.Cores.Nintendo.N64
 		public string Disassemble(MemoryDomain m, uint addr, out int length)
 		{
 			length = 4; // TODO: is this right?
-			var instruction = m.PeekWord(addr, true);
+			var instruction = m.PeekDWord(addr, true);
 
-			var result = api.m64p_decode_op((uint)instruction, (int)addr);
-			var strResult = Marshal.PtrToStringAnsi(result);
+			//TODO - reserve buffer here for disassembling into. allocating repeatedly will be slower
+			var result = api.m64p_decode_op(instruction, addr);
+			string strResult = Marshal.PtrToStringAnsi(result);
 
 			return strResult;
 		}
diff --git a/BizHawk.Emulation.Cores/Consoles/Nintendo/N64/NativeAPI/mupen64plusCoreApi.cs b/BizHawk.Emulation.Cores/Consoles/Nintendo/N64/NativeAPI/mupen64plusCoreApi.cs
index 7a7d64a359..13788635fe 100644
--- a/BizHawk.Emulation.Cores/Consoles/Nintendo/N64/NativeAPI/mupen64plusCoreApi.cs
+++ b/BizHawk.Emulation.Cores/Consoles/Nintendo/N64/NativeAPI/mupen64plusCoreApi.cs
@@ -265,8 +265,9 @@ namespace BizHawk.Emulation.Cores.Nintendo.N64.NativeApi
 		delegate m64p_error CoreDoCommandRenderCallback(m64p_command Command, int ParamInt, RenderCallback ParamPtr);
 		CoreDoCommandRenderCallback m64pCoreDoCommandRenderCallback;
 
+		//WARNING - RETURNS A STATIC BUFFER
 		[UnmanagedFunctionPointer(CallingConvention.Cdecl)]
-		public delegate IntPtr biz_r4300_decode_op(uint instr, int counter);
+		public delegate IntPtr biz_r4300_decode_op(uint instr, uint counter);
 		public biz_r4300_decode_op m64p_decode_op; 
 
 		/// <summary>
diff --git a/libmupen64plus/mupen64plus-core/src/debugger/dbg_decoder.c b/libmupen64plus/mupen64plus-core/src/debugger/dbg_decoder.c
index 7bda6d91b9..59d8340aec 100644
--- a/libmupen64plus/mupen64plus-core/src/debugger/dbg_decoder.c
+++ b/libmupen64plus/mupen64plus-core/src/debugger/dbg_decoder.c
@@ -799,27 +799,20 @@ r4k_disassemble_split_quick ( uint32_t instruction,
 
 #include "api/m64p_types.h"
 
-EXPORT char* CALL biz_r4300_decode_op(uint32 instr, int counter)
+//WARNING - RETURNS A STATIC BUFFER
+EXPORT char* CALL biz_r4300_decode_op(uint32 instr, uint32 counter)
 {
-	char * _final;
-	char * _op, * _args;
-    
-    _op = NULL;
-    _args = NULL;
-	_final = NULL;
-    
-    r4k_disassemble_split_quick(
-        instr,
-        counter,
-        &_op,
-        &_args
-    );
+	static char tmp[128];
+	static struct r4k_dis_t state;
+	memset( &state, 0, sizeof(state) );
+  r4k_disassemble(
+      &state,
+      instr,
+      counter,
+      tmp
+  );
 
-
-    //free( _op );
-	strcat(_op, " ");
-	strcat(_op, _args);
-	return _op;
+	return tmp;
 }
 
 //=-=-=-=-=-=-=-=-=-=-=-=-=-=-=[ DECODE_OP ]=-=-=-=-=-=-=-=-=-=-=-=-=-=-=[//