diff --git a/src/common/byte_stream.cpp b/src/common/byte_stream.cpp
index df1f01401..f380c2a4b 100644
--- a/src/common/byte_stream.cpp
+++ b/src/common/byte_stream.cpp
@@ -479,7 +479,7 @@ bool MemoryByteStream::WriteByte(u8 SourceByte)
 {
   if (m_iPosition < m_iSize)
   {
-    m_pMemory[m_iSize++] = SourceByte;
+    m_pMemory[m_iPosition++] = SourceByte;
     return true;
   }