diff --git a/src/BizHawk.Client.Common/RomGame.cs b/src/BizHawk.Client.Common/RomGame.cs
index a96cfa9f9f..737b480829 100644
--- a/src/BizHawk.Client.Common/RomGame.cs
+++ b/src/BizHawk.Client.Common/RomGame.cs
@@ -170,7 +170,7 @@ namespace BizHawk.Client.Common
 						// output[i + 1] = source[i + 2];
 						// output[i + 2] = source[i + 1];
 						byte temp = pSource[i];
-						pSource[i] = source[i + 3];
+						pSource[i] = pSource[i + 3];
 						pSource[i + 3] = temp;
 
 						temp = pSource[i + 1];