diff --git a/LEGO1/mxioinfo.cpp b/LEGO1/mxioinfo.cpp
index ebe2a480..09b5f194 100644
--- a/LEGO1/mxioinfo.cpp
+++ b/LEGO1/mxioinfo.cpp
@@ -1,4 +1,5 @@
 #include "mxioinfo.h"
+#include "ddraw.h"
 
 // OFFSET: LEGO1 0x100cc800
 MXIOINFO::MXIOINFO()
@@ -12,38 +13,331 @@ MXIOINFO::~MXIOINFO()
   Close(0);
 }
 
+// OFFSET: LEGO1 0x100cc8e0
+unsigned short MXIOINFO::Close(long arg)
+{
+  short result = 0;
+  if (m_info.hmmio != NULL)
+  {
+    result = Flush(0);
+
+    _lclose((HFILE)m_info.hmmio);
+    m_info.hmmio = NULL;
+
+    if (m_info.dwFlags & MMIO_ALLOCBUF)
+      free(m_info.pchBuffer);
+
+    m_info.pchEndWrite = NULL;
+    m_info.pchEndRead = NULL;
+    m_info.pchBuffer = NULL;
+    m_info.dwFlags = 0;
+  }
+  return result;
+}
+
 // OFFSET: LEGO1 0x100cc830
 unsigned short MXIOINFO::Open(const char *filename, DWORD fdwOpen)
 {
-  return 0;
-}
-
-// OFFSET: LEGO1 0x100cc8e0
-void MXIOINFO::Close(long arg)
-{
-  
+  _OFSTRUCT lpReOpenBuff;
+  unsigned short result = 0;
+
+  m_info.lBufOffset = 0;
+  m_info.lDiskOffset = 0;
+  m_info.hmmio = (HMMIO)OpenFile(filename, &lpReOpenBuff, (unsigned short)fdwOpen);
+
+  if (m_info.hmmio != (HMMIO)HFILE_ERROR)
+  {
+    m_info.dwFlags = fdwOpen;
+    if (m_info.dwFlags & MMIO_ALLOCBUF)
+    {
+      long currentLength = m_info.cchBuffer != 0 ? m_info.cchBuffer : 0x2000;
+
+      char* buffer = (char*)malloc(currentLength);
+      if (buffer == NULL)
+      {
+        m_info.cchBuffer = 0;
+        m_info.dwFlags &= ~MMIO_ALLOCBUF;
+        m_info.pchBuffer = NULL;
+        result = MMIOERR_OUTOFMEMORY;
+      }
+      else
+      {
+        m_info.cchBuffer = currentLength;
+        m_info.pchBuffer = buffer;
+      }
+      m_info.pchEndRead = m_info.pchBuffer;
+      m_info.pchNext = m_info.pchBuffer;
+      m_info.pchEndWrite = m_info.pchBuffer + m_info.cchBuffer;
+    }
+  }
+  else
+  {
+    result = MMIOERR_CANNOTOPEN;
+  }
+  return result;
 }
 
+// Not close to a match yet.
 // OFFSET: LEGO1 0x100cc930
 unsigned long MXIOINFO::Read(HPSTR pch, LONG cch)
 {
-  return 0;
+  long result = 0;
+  if (m_info.pchBuffer != NULL)
+  {
+    LONG toRead = m_info.pchEndRead - m_info.pchNext;
+    unsigned long remaining = cch;
+    do
+    {
+      if (toRead > 0) {
+        if (toRead > remaining) {
+          toRead = remaining;
+        }
+        remaining -= toRead;
+        memcpy(pch, m_info.pchNext, toRead);
+        m_info.pchNext += toRead;
+      }
+    } while (remaining && !Something(0) && m_info.pchEndRead - m_info.pchNext >= 1);
+  }
+  else
+  {
+    if (m_info.hmmio != NULL && cch > 0) {
+      result = _hread((HFILE)m_info.hmmio, pch, cch);
+      if (result == -1) {
+        result = 0;
+        m_info.lDiskOffset = GetCurrentOffset();
+      }
+      else
+      {
+        m_info.lDiskOffset += result;
+      }
+    }
+  }
+
+  return result;
 }
 
+// First attemp, not particularly close, see some sensible logic of what the 
+// function is trying to do.
 // OFFSET: LEGO1 0x100cca00
 LONG MXIOINFO::Seek(LONG lOffset, int iOrigin)
 {
-  return 0;
+  LONG result = -1;
+  if (m_info.pchBuffer != NULL)
+  {
+    // Convert to SEEK_SET
+    if (iOrigin == SEEK_CUR) {
+      if (lOffset == 0) {
+        // Nothing to do
+        return (LONG)(m_info.pchNext + m_info.lBufOffset - m_info.pchBuffer);
+      } else {
+        iOrigin = 0;
+        lOffset = (LONG)(m_info.pchNext + lOffset + m_info.lBufOffset - m_info.pchBuffer);
+      }
+    } else if (iOrigin == SEEK_END) {
+      // Not implemented
+      return -1;
+    }
+
+    // Seek distance is already within the buffer
+    if ((m_info.lBufOffset <= lOffset) && (lOffset < m_info.cchBuffer + m_info.lBufOffset)) {
+      m_info.pchNext = m_info.pchBuffer + lOffset - m_info.lBufOffset;
+      return lOffset;
+    }
+
+    // Do SEEK_CUR on the underlying file handle
+    if (m_info.hmmio != NULL) {
+      short result = Flush(0);
+      if (result == 0) {
+        LONG newOffset = _llseek((HFILE)m_info.hmmio, lOffset, iOrigin);
+        m_info.lDiskOffset = newOffset;
+        if (newOffset == -1) {
+          m_info.lDiskOffset = GetCurrentOffset();
+          return -1;
+        }
+        LONG wholeBlockOffset = lOffset - (int)(lOffset % m_info.cchBuffer);
+        m_info.lBufOffset = wholeBlockOffset;
+        if (lOffset != wholeBlockOffset) {
+          LONG newOffset2 = _llseek((HFILE)m_info.hmmio, wholeBlockOffset, 0);
+          m_info.lDiskOffset = newOffset2;
+          if (newOffset2 == -1) {
+            m_info.lDiskOffset = GetCurrentOffset();
+          }
+        }
+        if (m_info.lDiskOffset == m_info.lBufOffset) {
+          DWORD rw = m_info.dwFlags & MMIO_RWMODE;
+          if (rw != MMIO_READ && rw != MMIO_READWRITE) {
+            m_info.pchNext = m_info.pchBuffer + lOffset - m_info.lBufOffset;
+            return lOffset;
+          }
+          LONG bytesRead = _hread((HFILE)m_info.hmmio, m_info.pchBuffer, m_info.cchBuffer);
+          if (bytesRead == -1) {
+            m_info.lDiskOffset = GetCurrentOffset();
+            return -1;
+          }
+          m_info.lDiskOffset += bytesRead;
+          m_info.pchNext = m_info.pchBuffer + lOffset - m_info.lBufOffset;
+          m_info.pchEndRead = m_info.pchBuffer + bytesRead;
+          if (m_info.pchNext < m_info.pchEndRead) {
+            return lOffset;
+          }
+        }
+      }
+    }
+  }
+  else
+  {
+    if (m_info.hmmio != NULL) {
+      if ((iOrigin == SEEK_CUR) && (lOffset == 0)) {
+        return m_info.lDiskOffset;
+      }
+      result = _llseek((HFILE)m_info.hmmio, lOffset, iOrigin);
+      m_info.lDiskOffset = result;
+      if (result == HFILE_ERROR) {
+        m_info.lDiskOffset = GetCurrentOffset();
+      }
+    }
+  }
+  return result;
 }
 
+// Matching except for swap of EAX and ECX
 // OFFSET: LEGO1 0x100ccbc0
-void MXIOINFO::SetBuffer(LPSTR pchBuffer, LONG cchBuffer, LONG unk)
+unsigned short MXIOINFO::SetBuffer(LPSTR pchBuffer, LONG cchBuffer, UINT fuBuffer)
 {
-  
+  unsigned short ret = Flush(0);
+  if (m_info.dwFlags & MMIO_ALLOCBUF)
+  {
+    m_info.dwFlags &= ~MMIO_ALLOCBUF;
+    free(m_info.pchBuffer);
+  }
+  m_info.pchBuffer = pchBuffer;
+  m_info.cchBuffer = cchBuffer;
+  m_info.pchEndRead = pchBuffer;
+  m_info.pchEndWrite = pchBuffer + cchBuffer;
+  return ret;
 }
 
 // OFFSET: LEGO1 0x100cce60
 unsigned short MXIOINFO::Descend(LPMMCKINFO pmmcki, const MMCKINFO *pmmckiParent, UINT fuDescend)
 {
   return 0;
+}
+
+// Not a close match, but the behavior looks reasonable.
+// OFFSET: LEGO1 0x100ccc10
+unsigned short MXIOINFO::Flush(int arg)
+{
+  unsigned short result = 0;
+  if (m_info.dwFlags & MMIO_DIRTY)
+  {
+    if (m_info.pchBuffer == NULL) 
+    {
+      result = MMIOERR_UNBUFFERED;
+    }
+    else
+    {
+      if (m_info.hmmio == NULL || (m_info.dwFlags & MMIO_RWMODE) == 0)
+      {
+        return MMIOERR_CANNOTWRITE;
+      }
+      if (m_info.cchBuffer > 0)
+      {
+        if (m_info.lDiskOffset != m_info.lBufOffset)
+        {
+          m_info.lDiskOffset = _llseek((HFILE)m_info.hmmio, m_info.lBufOffset, 0);
+        }
+        if (m_info.lBufOffset == m_info.lDiskOffset)
+        {
+          long written = _hwrite((HFILE)m_info.hmmio, m_info.pchBuffer, m_info.cchBuffer);
+          if (written != -1 && m_info.cchBuffer == written)
+          {
+            m_info.lDiskOffset += written;
+            m_info.dwFlags &= ~MMIO_DIRTY;
+            m_info.pchNext = m_info.pchBuffer;
+            return 0;
+          }
+          m_info.lDiskOffset = GetCurrentOffset();
+          return MMIOERR_CANNOTWRITE;
+        }
+        m_info.lDiskOffset = GetCurrentOffset();
+        return MMIOERR_CANNOTSEEK;
+      }
+    }
+  }
+  return result;
+}
+
+// 97% Match, just two locations have the order of an == comparison swapped.
+// I suspect this isn't how the code was originally written, because I have to
+// include an empty if branch to get the code almost matching, though it is a
+// place where you logically could have an empty block.
+// OFFSET: LEGO1 0x100ccd00
+unsigned short MXIOINFO::Something(UINT flags)
+{
+  short result = 0;
+  DWORD rwState = m_info.dwFlags & MMIO_RWMODE;
+  if (m_info.pchBuffer != NULL)
+  {
+    LONG cchBuffer = m_info.cchBuffer;
+    if (((rwState == MMIO_WRITE) || (rwState == MMIO_READWRITE)) && (m_info.dwFlags & MMIO_DIRTY))
+    {
+      if (((flags & MMIO_WRITE) || (rwState == MMIO_READWRITE)) && (cchBuffer > 0))
+      {
+        if (m_info.lDiskOffset != m_info.lBufOffset) {
+          m_info.lDiskOffset = _llseek((HFILE)m_info.hmmio, m_info.lBufOffset, 0);
+        }
+        if (m_info.lDiskOffset != m_info.lBufOffset)
+        {
+          result = MMIOERR_CANNOTSEEK;
+          m_info.lDiskOffset = GetCurrentOffset();
+        }
+        else
+        {
+          LONG bytesWritten = _hwrite((HFILE)m_info.hmmio, m_info.pchBuffer, cchBuffer);
+          if ((bytesWritten != -1) && (cchBuffer == bytesWritten)) {
+            m_info.lDiskOffset += bytesWritten;
+            m_info.dwFlags = m_info.dwFlags & ~MMIO_DIRTY;
+            m_info.pchNext = m_info.pchBuffer;
+            m_info.pchEndRead = m_info.pchBuffer;
+          }
+          else
+          {
+            result = MMIOERR_CANNOTWRITE;
+            m_info.lDiskOffset = GetCurrentOffset();
+          }
+        }
+      }
+    }
+
+    m_info.lBufOffset = m_info.lBufOffset + cchBuffer;
+    if (((rwState != MMIO_READ) && (rwState != MMIO_READWRITE)) || cchBuffer <= 0) {
+      // Nothing to do
+    }
+    else
+    {
+      if (m_info.lDiskOffset != m_info.lBufOffset) {
+        m_info.lDiskOffset = _llseek((HFILE)m_info.hmmio, m_info.lBufOffset, 0);
+      }
+      if (m_info.lDiskOffset != m_info.lBufOffset) {
+        result = MMIOERR_CANNOTSEEK;
+        m_info.lDiskOffset = GetCurrentOffset();
+      } else {
+        LONG bytesRead = _hread((HFILE)m_info.hmmio, m_info.pchBuffer, cchBuffer);
+        if (bytesRead == -1) {
+          result = MMIOERR_CANNOTREAD;
+          m_info.lDiskOffset = GetCurrentOffset();
+        } else {
+          m_info.lDiskOffset += bytesRead;
+          m_info.pchNext = m_info.pchBuffer;
+          m_info.pchEndRead = m_info.pchBuffer + bytesRead;
+          return result;
+        }
+      }
+    }
+  }
+  else
+  {
+    result = MMIOERR_UNBUFFERED;
+  }
+  return result;
 }
\ No newline at end of file
diff --git a/LEGO1/mxioinfo.h b/LEGO1/mxioinfo.h
index c88a55b9..32d161a1 100644
--- a/LEGO1/mxioinfo.h
+++ b/LEGO1/mxioinfo.h
@@ -12,11 +12,15 @@ class MXIOINFO
   __declspec(dllexport) ~MXIOINFO();
 
   unsigned short Open(const char *filename, DWORD fdwOpen);
-  void Close(long arg);
+  unsigned short Close(long arg);
   LONG Seek(LONG lOffset, int iOrigin);
   unsigned long Read(HPSTR pch, LONG cch);
-  void SetBuffer(LPSTR pchBuffer, LONG cchBuffer, LONG unk);
+  unsigned short SetBuffer(LPSTR pchBuffer, LONG cchBuffer, UINT fuBuffer);
   unsigned short Descend(LPMMCKINFO pmmcki, const MMCKINFO *pmmckiParent, UINT fuDescend);
+  unsigned short Flush(int arg);
+  unsigned short Something(UINT flags);
+
+  inline LONG GetCurrentOffset() { return _llseek((HFILE)m_info.hmmio, 0, SEEK_CUR); }
 
   MMIOINFO m_info;
 };