diff --git a/BizHawk.Emulation.Cores/Consoles/Nintendo/NES/FDS/FDSAudio.cs b/BizHawk.Emulation.Cores/Consoles/Nintendo/NES/FDS/FDSAudio.cs
index 81897de1b8..715966295d 100644
--- a/BizHawk.Emulation.Cores/Consoles/Nintendo/NES/FDS/FDSAudio.cs
+++ b/BizHawk.Emulation.Cores/Consoles/Nintendo/NES/FDS/FDSAudio.cs
@@ -326,9 +326,13 @@ namespace BizHawk.Emulation.Cores.Nintendo.NES
 					break;
 				case 0x4088:
 					// write twice into virtual 64 unit buffer
-					Buffer.BlockCopy(modtable, 2, modtable, 0, 62);
-					modtable[62] = (byte)(value & 7);
-					modtable[63] = (byte)(value & 7);
+					//Buffer.BlockCopy(modtable, 2, modtable, 0, 62);
+					modtable[modtablepos] = (byte)(value & 7);
+					modtablepos++;
+					modtablepos &= 63;
+					modtable[modtablepos] = (byte)(value & 7);
+					modtablepos++;
+					modtablepos &= 63;
 					break;
 				case 0x4089:
 					switch (value & 3)
@@ -368,4 +372,4 @@ namespace BizHawk.Emulation.Cores.Nintendo.NES
 			return ret;
 		}
 	}
-}
+}
\ No newline at end of file