diff --git a/BurnOutSharp/External/libmspack/CAB/DataBlockHeader.cs b/BurnOutSharp/External/libmspack/CAB/DataBlockHeader.cs
deleted file mode 100644
index 42471e8a..00000000
--- a/BurnOutSharp/External/libmspack/CAB/DataBlockHeader.cs
+++ /dev/null
@@ -1,58 +0,0 @@
-/* This file is part of libmspack.
- * (C) 2003-2018 Stuart Caie.
- *
- * libmspack is free software; you can redistribute it and/or modify it under
- * the terms of the GNU Lesser General Public License (LGPL) version 2.1
- *
- * For further details, see the file COPYING.LIB distributed with libmspack
- */
-
-using System;
-
-namespace LibMSPackSharp.CAB
-{
-    public class DataBlockHeader
-    {
-        #region Fields
-
-        /// <summary>
-        /// CRC32 checksum of the data
-        /// </summary>
-        public uint Checksum { get; private set; }
-
-        /// <summary>
-        /// Compressed size of the data
-        /// </summary>
-        public ushort CompressedSize { get; private set; }
-
-        /// <summary>
-        /// Uncompressed size of the data
-        /// </summary>
-        public ushort UncompressedSize { get; private set; }
-
-        #endregion
-
-        /// <summary>
-        /// Private constructor
-        /// </summary>
-        private DataBlockHeader() { }
-
-        /// <summary>
-        /// Constructor
-        /// </summary>
-        public static Error Create(byte[] data, out DataBlockHeader header)
-        {
-            header = null;
-            if (data == null || data.Length < 0x08)
-                return Error.MSPACK_ERR_READ;
-
-            header = new DataBlockHeader();
-
-            header.Checksum = BitConverter.ToUInt32(data, 0x00);
-            header.CompressedSize = BitConverter.ToUInt16(data, 0x04);
-            header.UncompressedSize = BitConverter.ToUInt16(data, 0x06);
-
-            return Error.MSPACK_ERR_OK;
-        }
-    }
-}
diff --git a/BurnOutSharp/External/libmspack/CAB/Decompressor.cs b/BurnOutSharp/External/libmspack/CAB/Decompressor.cs
index f5e1677a..4df5b439 100644
--- a/BurnOutSharp/External/libmspack/CAB/Decompressor.cs
+++ b/BurnOutSharp/External/libmspack/CAB/Decompressor.cs
@@ -23,8 +23,8 @@ namespace LibMSPackSharp.CAB
     /// 
     /// All fields are READ ONLY.
     /// </summary>
-    /// <see cref="mspack_create_cab_decompressor()"/>
-    /// <see cref="mspack_destroy_cab_decompressor()"/>
+    /// <see cref="Library.CreateCABDecompressor(SystemImpl)"/>
+    /// <see cref="Library.DestroyCABDecompressor(Decompressor)"/>
     public class Decompressor
     {
         /// <summary>
diff --git a/BurnOutSharp/External/libmspack/CAB/Implementation.cs b/BurnOutSharp/External/libmspack/CAB/Implementation.cs
index b11b2367..7c6b1deb 100644
--- a/BurnOutSharp/External/libmspack/CAB/Implementation.cs
+++ b/BurnOutSharp/External/libmspack/CAB/Implementation.cs
@@ -142,7 +142,7 @@ namespace LibMSPackSharp.CAB
         /// </summary>
         public static CabinetImpl Open(Decompressor d, string filename)
         {
-            DecompressorImpl self = (DecompressorImpl)d;
+            DecompressorImpl self = d as DecompressorImpl;
             CabinetImpl cab = null;
 
             if (self == null)
@@ -181,7 +181,7 @@ namespace LibMSPackSharp.CAB
         /// </summary>
         public static void Close(Decompressor d, Cabinet origcab)
         {
-            DecompressorImpl self = (DecompressorImpl)d;
+            DecompressorImpl self = d as DecompressorImpl;
 
             FolderData dat, ndat;
             Cabinet cab, ncab;
@@ -222,7 +222,7 @@ namespace LibMSPackSharp.CAB
                     }
 
                     // Free folder data segments
-                    for (dat = ((FolderImpl)fol).Data.Next; dat != null; dat = ndat)
+                    for (dat = (fol as FolderImpl).Data.Next; dat != null; dat = ndat)
                     {
                         ndat = dat.Next;
                         sys.Free(dat);
@@ -472,7 +472,7 @@ namespace LibMSPackSharp.CAB
                         file.Folder = ifol;
 
                         // Set "merge next" pointer
-                        fol = (FolderImpl)ifol;
+                        fol = ifol as FolderImpl;
                         if (fol.MergeNext == null)
                             fol.MergeNext = file;
                     }
@@ -483,7 +483,7 @@ namespace LibMSPackSharp.CAB
                         file.Folder = cab.Folders;
 
                         // Set "merge prev" pointer
-                        fol = (FolderImpl)file.Folder;
+                        fol = file.Folder as FolderImpl;
                         if (fol.MergePrev == null)
                             fol.MergePrev = file;
                     }
@@ -594,7 +594,7 @@ namespace LibMSPackSharp.CAB
         /// </summary>
         public static Cabinet Search(Decompressor d, string filename)
         {
-            DecompressorImpl self = (DecompressorImpl)d;
+            DecompressorImpl self = d as DecompressorImpl;
 
             if (self == null)
                 return null;
@@ -839,7 +839,7 @@ namespace LibMSPackSharp.CAB
         /// </summary>
         public static Error Merge(Decompressor d, Cabinet lcab, Cabinet rcab)
         {
-            DecompressorImpl self = (DecompressorImpl)d;
+            DecompressorImpl self = d as DecompressorImpl;
 
             FolderData data, ndata;
             FolderImpl lfol, rfol;
@@ -891,11 +891,11 @@ namespace LibMSPackSharp.CAB
                 sys.Message(null, "WARNING; merged cabinets with odd order.");
 
             // Merging the last folder in lcab with the first folder in rcab
-            lfol = (FolderImpl)lcab.Folders;
-            rfol = (FolderImpl)rcab.Folders;
+            lfol = lcab.Folders as FolderImpl;
+            rfol = rcab.Folders as FolderImpl;
             while (lfol.Next != null)
             {
-                lfol = (FolderImpl)lfol.Next;
+                lfol = lfol.Next as FolderImpl;
             }
 
             // Do we need to merge folders?
@@ -1086,7 +1086,7 @@ namespace LibMSPackSharp.CAB
         /// </summary>
         public static Error Extract(Decompressor d, InternalFile file, string filename)
         {
-            DecompressorImpl self = (DecompressorImpl)d;
+            DecompressorImpl self = d as DecompressorImpl;
             object fh;
 
             if (self == null)
@@ -1095,7 +1095,7 @@ namespace LibMSPackSharp.CAB
                 return self.Error = Error.MSPACK_ERR_ARGS;
 
             SystemImpl sys = self.System;
-            FolderImpl fol = (FolderImpl)file.Folder;
+            FolderImpl fol = file.Folder as FolderImpl;
 
             // If offset is beyond 2GB, nothing can be extracted
             if (file.Offset > CAB_LENGTHMAX)
@@ -1278,19 +1278,19 @@ namespace LibMSPackSharp.CAB
             switch (self.State.CompressionType & CompressionType.COMPTYPE_MASK)
             {
                 case CompressionType.COMPTYPE_NONE:
-                    NoneFree((NoneState)self.State.DecompressorState);
+                    NoneFree(self.State.DecompressorState);
                     break;
 
                 case CompressionType.COMPTYPE_MSZIP:
-                    MSZIP.Free((MSZIPDStream)self.State.DecompressorState);
+                    MSZIP.Free(self.State.DecompressorState);
                     break;
 
                 case CompressionType.COMPTYPE_QUANTUM:
-                    QTM.Free((QTMDStream)self.State.DecompressorState);
+                    QTM.Free(self.State.DecompressorState);
                     break;
 
                 case CompressionType.COMPTYPE_LZX:
-                    LZX.Free((LZXDStream)self.State.DecompressorState);
+                    LZX.Free(self.State.DecompressorState);
                     break;
             }
 
@@ -1309,7 +1309,7 @@ namespace LibMSPackSharp.CAB
         /// </summary>
         private static int SysRead(object file, byte[] buffer, int pointer, int bytes)
         {
-            DecompressorImpl self = (DecompressorImpl)file;
+            DecompressorImpl self = file as DecompressorImpl;
             SystemImpl sys = self.System;
             int avail, todo, outlen = 0;
 
@@ -1370,7 +1370,7 @@ namespace LibMSPackSharp.CAB
                         {
                             // Special LZX hack -- on the last block, inform LZX of the
                             // size of the output data stream.
-                            LZX.SetOutputLength((LZXDStream)self.State.DecompressorState, self.State.Outlen);
+                            LZX.SetOutputLength(self.State.DecompressorState as LZXDStream, self.State.Outlen);
                         }
                     }
                 }
@@ -1387,7 +1387,7 @@ namespace LibMSPackSharp.CAB
         /// </summary>
         private static int SysWrite(object file, byte[] buffer, int pointer, int bytes)
         {
-            DecompressorImpl self = (DecompressorImpl)file;
+            DecompressorImpl self = file as DecompressorImpl;
             self.State.Offset += (uint)bytes;
             if (self.State.OutputFileHandle != null)
                 return self.System.Write(self.State.OutputFileHandle, buffer, pointer, bytes);
@@ -1576,7 +1576,7 @@ namespace LibMSPackSharp.CAB
 
         internal static void NoneFree(object s)
         {
-            NoneState state = (NoneState)s;
+            NoneState state = s as NoneState;
             if (state != null)
             {
                 SystemImpl sys = state.Sys;
@@ -1594,7 +1594,7 @@ namespace LibMSPackSharp.CAB
         /// </summary>
         public static Error Param(Decompressor d, Parameters param, int value)
         {
-            DecompressorImpl self = (DecompressorImpl)d;
+            DecompressorImpl self = d as DecompressorImpl;
             if (self == null)
                 return Error.MSPACK_ERR_ARGS;
 
@@ -1638,7 +1638,7 @@ namespace LibMSPackSharp.CAB
         /// </summary>
         public static Error LastError(Decompressor d)
         {
-            DecompressorImpl self = (DecompressorImpl)d;
+            DecompressorImpl self = d as DecompressorImpl;
             return (self != null) ? self.Error : Error.MSPACK_ERR_ARGS;
         }
 
diff --git a/BurnOutSharp/External/libmspack/CHM/Implementation.cs b/BurnOutSharp/External/libmspack/CHM/Implementation.cs
index 3f5f990e..2b114e3f 100644
--- a/BurnOutSharp/External/libmspack/CHM/Implementation.cs
+++ b/BurnOutSharp/External/libmspack/CHM/Implementation.cs
@@ -144,7 +144,7 @@ namespace LibMSPackSharp.CHM
         /// </summary>
         private static Header RealOpen(Decompressor d, string filename, bool entire)
         {
-            DecompressorImpl self = (DecompressorImpl)d;
+            DecompressorImpl self = d as DecompressorImpl;
             Header chm = null;
 
             if (d == null)
@@ -194,7 +194,7 @@ namespace LibMSPackSharp.CHM
         /// </summary>
         public static void Close(Decompressor d, Header chm)
         {
-            DecompressorImpl self = (DecompressorImpl)d;
+            DecompressorImpl self = d as DecompressorImpl;
             DecompressFile fi, nfi;
             uint i;
 
@@ -529,7 +529,7 @@ namespace LibMSPackSharp.CHM
 
                     fi.Next = null;
                     fi.Filename = Encoding.UTF8.GetString(chunk, name, (int)nameLen) + "\0";
-                    fi.Section = (section == 0) ? (Section)chm.Sec0 : (Section)chm.Sec1;
+                    fi.Section = (section == 0) ? chm.Sec0 as Section : chm.Sec1 as Section;
                     fi.Offset = offset;
                     fi.Length = length;
 
@@ -590,7 +590,7 @@ namespace LibMSPackSharp.CHM
         /// </summary>
         public static Error FastFind(Decompressor d, Header chm, string filename, DecompressFile f_ptr)
         {
-            DecompressorImpl self = (DecompressorImpl)d;
+            DecompressorImpl self = d as DecompressorImpl;
             SystemImpl sys;
             object fh;
 
@@ -682,7 +682,7 @@ namespace LibMSPackSharp.CHM
                     sec = (uint)((sec << 7) | (chunk[p] & 0x7F));
                 } while ((chunk[p++] & 0x80) != 0);
 
-                f_ptr.Section = (sec == 0) ? (Section)chm.Sec0 : (Section)chm.Sec1;
+                f_ptr.Section = sec == 0 ? chm.Sec0 as Section : chm.Sec1 as Section;
 
                 // READ_ENCINT(f_ptr.Offset)
                 f_ptr.Offset = 0;
@@ -996,7 +996,7 @@ namespace LibMSPackSharp.CHM
         /// </summary>
         public static Error Extract(Decompressor d, DecompressFile file, string filename)
         {
-            DecompressorImpl self = (DecompressorImpl)d;
+            DecompressorImpl self = d as DecompressorImpl;
             if (self == null)
                 return Error.MSPACK_ERR_ARGS;
 
@@ -1154,7 +1154,7 @@ namespace LibMSPackSharp.CHM
         /// </summary>
         private static int SysWrite(object file, byte[] buffer, int offset, int bytes)
         {
-            DecompressorImpl self = (DecompressorImpl)file;
+            DecompressorImpl self = file as DecompressorImpl;
             self.State.Offset += bytes;
             if (self.State.OutputFileHandle != null)
                 return self.System.Write(self.State.OutputFileHandle, buffer, offset, bytes);
@@ -1175,10 +1175,9 @@ namespace LibMSPackSharp.CHM
         {
             int window_size, window_bits, reset_interval, entry;
             SystemImpl sys = self.System;
-            MSCompressedSection sec;
             byte[] data;
 
-            sec = (MSCompressedSection)file.Section;
+            MSCompressedSection sec = file.Section as MSCompressedSection;
 
             // Ensure we have a mscompressed content section
             DecompressFile contentFile = null;
@@ -1531,7 +1530,7 @@ namespace LibMSPackSharp.CHM
         /// <returns></returns>
         public static Error LastError(Decompressor d)
         {
-            DecompressorImpl self = (DecompressorImpl)d;
+            DecompressorImpl self = d as DecompressorImpl;
             return (self != null ? self.Error : Error.MSPACK_ERR_ARGS);
         }
 
diff --git a/BurnOutSharp/External/libmspack/Compression/DES.cs b/BurnOutSharp/External/libmspack/Compression/DES.cs
index 46e49ed9..384ac8c6 100644
--- a/BurnOutSharp/External/libmspack/Compression/DES.cs
+++ b/BurnOutSharp/External/libmspack/Compression/DES.cs
@@ -9,7 +9,7 @@
 
 namespace LibMSPackSharp.Compression
 {
-    public class des
+    public class DES
     {
     }
 }
diff --git a/BurnOutSharp/External/libmspack/Compression/LZX.cs b/BurnOutSharp/External/libmspack/Compression/LZX.cs
index 1946c7c2..550a12df 100644
--- a/BurnOutSharp/External/libmspack/Compression/LZX.cs
+++ b/BurnOutSharp/External/libmspack/Compression/LZX.cs
@@ -426,7 +426,7 @@ namespace LibMSPackSharp.Compression
         /// <returns>an error code, or MSPACK_ERR_OK if successful</returns>
         public static Error Decompress(object o, long outBytes)
         {
-            LZXDStream lzx = (LZXDStream)o;
+            LZXDStream lzx = o as LZXDStream;
             if (lzx == null)
                 return Error.MSPACK_ERR_ARGS;
 
@@ -1055,8 +1055,9 @@ namespace LibMSPackSharp.Compression
         /// system.free() using the system pointer given in lzxd_init().
         /// </summary>
         /// <param name="lzx">LZX decompression state to free.</param>
-        public static void Free(LZXDStream lzx)
+        public static void Free(object s)
         {
+            LZXDStream lzx = s as LZXDStream;
             if (lzx != null)
             {
                 SystemImpl sys = lzx.Sys;
diff --git a/BurnOutSharp/External/libmspack/Compression/MSZIP.cs b/BurnOutSharp/External/libmspack/Compression/MSZIP.cs
index ad441606..61403587 100644
--- a/BurnOutSharp/External/libmspack/Compression/MSZIP.cs
+++ b/BurnOutSharp/External/libmspack/Compression/MSZIP.cs
@@ -162,7 +162,7 @@ namespace LibMSPackSharp.Compression
         /// </summary>
         public static Error Decompress(object o, long out_bytes)
         {
-            MSZIPDStream zip = (MSZIPDStream)o;
+            MSZIPDStream zip = o as MSZIPDStream;
             if (zip == null)
                 return Error.MSPACK_ERR_ARGS;
 
@@ -328,8 +328,9 @@ namespace LibMSPackSharp.Compression
         /// 
         /// - calls system.free() using the system pointer given in mszipd_init()
         /// </summary>
-        public static void Free(MSZIPDStream zip)
+        public static void Free(object s)
         {
+            MSZIPDStream zip = s as MSZIPDStream;
             if (zip != null)
             {
                 SystemImpl sys = zip.Sys;
diff --git a/BurnOutSharp/External/libmspack/Compression/QTM.cs b/BurnOutSharp/External/libmspack/Compression/QTM.cs
index d649355c..463cf025 100644
--- a/BurnOutSharp/External/libmspack/Compression/QTM.cs
+++ b/BurnOutSharp/External/libmspack/Compression/QTM.cs
@@ -171,7 +171,7 @@ namespace LibMSPackSharp.Compression
         /// </summary>
         public static Error Decompress(object o, long out_bytes)
         {
-            QTMDStream qtm = (QTMDStream)o;
+            QTMDStream qtm = o as QTMDStream;
             if (qtm == null)
                 return Error.MSPACK_ERR_ARGS;
 
@@ -466,8 +466,9 @@ namespace LibMSPackSharp.Compression
         /// Frees all state associated with a Quantum data stream
         /// - calls system.free() using the system pointer given in qtmd_init()
         /// </summary>
-        public static void Free(QTMDStream qtm)
+        public static void Free(object s)
         {
+            QTMDStream qtm = s as QTMDStream;
             if (qtm != null)
             {
                 SystemImpl sys = qtm.Sys;
@@ -489,28 +490,28 @@ namespace LibMSPackSharp.Compression
             ref int i_ptr, ref int i_end, ref uint bit_buffer, ref uint bits_left)
         {
             range = (uint)(((high - low) & 0xFFFF) + 1);
-            symf = (ushort)(((((current - low + 1) * model.Syms[0].CumFreq) - 1) / range) & 0xFFFF);
+            symf = (ushort)(((((current - low + 1) * model.Syms[0].CumulativeFrequency) - 1) / range) & 0xFFFF);
 
             int i;
             for (i = 1; i < model.Entries; i++)
             {
-                if (model.Syms[i].CumFreq <= symf)
+                if (model.Syms[i].CumulativeFrequency <= symf)
                     break;
             }
 
             var = model.Syms[i - 1].Sym;
 
             range = (ushort)((high - low) + 1);
-            symf = model.Syms[0].CumFreq;
-            high = (ushort)(low + ((model.Syms[i - 1].CumFreq * range) / symf) - 1);
-            low = (ushort)(low + ((model.Syms[i].CumFreq * range) / symf));
+            symf = model.Syms[0].CumulativeFrequency;
+            high = (ushort)(low + ((model.Syms[i - 1].CumulativeFrequency * range) / symf) - 1);
+            low = (ushort)(low + ((model.Syms[i].CumulativeFrequency * range) / symf));
 
             do
             {
-                model.Syms[--i].CumFreq += 8;
+                model.Syms[--i].CumulativeFrequency += 8;
             } while (i > 0);
 
-            if (model.Syms[0].CumFreq > 3800)
+            if (model.Syms[0].CumulativeFrequency > 3800)
                 UpdateModel(model);
 
             while (true)
@@ -548,10 +549,10 @@ namespace LibMSPackSharp.Compression
                 for (i = model.Entries - 1; i >= 0; i--)
                 {
                     /* -1, not -2; the 0 entry saves this */
-                    model.Syms[i].CumFreq >>= 1;
-                    if (model.Syms[i].CumFreq <= model.Syms[i + 1].CumFreq)
+                    model.Syms[i].CumulativeFrequency >>= 1;
+                    if (model.Syms[i].CumulativeFrequency <= model.Syms[i + 1].CumulativeFrequency)
                     {
-                        model.Syms[i].CumFreq = (ushort)(model.Syms[i + 1].CumFreq + 1);
+                        model.Syms[i].CumulativeFrequency = (ushort)(model.Syms[i + 1].CumulativeFrequency + 1);
                     }
                 }
             }
@@ -563,9 +564,9 @@ namespace LibMSPackSharp.Compression
                     // No -1, want to include the 0 entry
 
                     // This converts CumFreqs into frequencies, then shifts right
-                    model.Syms[i].CumFreq -= model.Syms[i + 1].CumFreq;
-                    model.Syms[i].CumFreq++; // Avoid losing things entirely
-                    model.Syms[i].CumFreq >>= 1;
+                    model.Syms[i].CumulativeFrequency -= model.Syms[i + 1].CumulativeFrequency;
+                    model.Syms[i].CumulativeFrequency++; // Avoid losing things entirely
+                    model.Syms[i].CumulativeFrequency >>= 1;
                 }
 
                 // Now sort by frequencies, decreasing order -- this must be an
@@ -575,7 +576,7 @@ namespace LibMSPackSharp.Compression
                 {
                     for (j = i + 1; j < model.Entries; j++)
                     {
-                        if (model.Syms[i].CumFreq < model.Syms[j].CumFreq)
+                        if (model.Syms[i].CumulativeFrequency < model.Syms[j].CumulativeFrequency)
                         {
                             tmp = model.Syms[i];
                             model.Syms[i] = model.Syms[j];
@@ -587,7 +588,7 @@ namespace LibMSPackSharp.Compression
                 // Then convert frequencies back to CumFreq
                 for (i = model.Entries - 1; i >= 0; i--)
                 {
-                    model.Syms[i].CumFreq += model.Syms[i + 1].CumFreq;
+                    model.Syms[i].CumulativeFrequency += model.Syms[i + 1].CumulativeFrequency;
                 }
             }
         }
@@ -604,7 +605,7 @@ namespace LibMSPackSharp.Compression
                 syms[i].Sym = (ushort)(start + i);
 
                 // Current frequency of that symbol
-                syms[i].CumFreq = (ushort)(len - i);
+                syms[i].CumulativeFrequency = (ushort)(len - i);
             }
         }
     }
diff --git a/BurnOutSharp/External/libmspack/Compression/QTMDModelSym.cs b/BurnOutSharp/External/libmspack/Compression/QTMDModelSym.cs
index b01da6e6..75af0fda 100644
--- a/BurnOutSharp/External/libmspack/Compression/QTMDModelSym.cs
+++ b/BurnOutSharp/External/libmspack/Compression/QTMDModelSym.cs
@@ -16,6 +16,6 @@ namespace LibMSPackSharp.Compression
     {
         public ushort Sym { get; set; }
 
-        public ushort CumFreq { get; set; }
+        public ushort CumulativeFrequency { get; set; }
     }
 }
diff --git a/BurnOutSharp/External/libmspack/KWAJ/Implementation.cs b/BurnOutSharp/External/libmspack/KWAJ/Implementation.cs
index 36214146..448f659f 100644
--- a/BurnOutSharp/External/libmspack/KWAJ/Implementation.cs
+++ b/BurnOutSharp/External/libmspack/KWAJ/Implementation.cs
@@ -109,7 +109,7 @@ namespace LibMSPackSharp.KWAJ
         /// </summary>
         public static Header Open(Decompressor d, string filename)
         {
-            DecompressorImpl self = (DecompressorImpl)d;
+            DecompressorImpl self = d as DecompressorImpl;
             if (self == null)
                 return null;
 
@@ -151,10 +151,10 @@ namespace LibMSPackSharp.KWAJ
         /// </summary>
         public static void Close(Decompressor d, Header hdr)
         {
-            DecompressorImpl self = (DecompressorImpl)d;
-            HeaderImpl hdr_p = (HeaderImpl)hdr;
+            DecompressorImpl self = d as DecompressorImpl;
+            HeaderImpl hdr_p = hdr as HeaderImpl;
 
-            if (self == null || self.System == null)
+            if (self?.System == null || hdr_p == null)
                 return;
 
             // Close the file handle associated
@@ -319,14 +319,16 @@ namespace LibMSPackSharp.KWAJ
         /// </summary>
         public static Error Extract(Decompressor d, Header hdr, string filename)
         {
-            DecompressorImpl self = (DecompressorImpl)d;
+            DecompressorImpl self = d as DecompressorImpl;
             if (self == null)
                 return Error.MSPACK_ERR_ARGS;
             if (hdr == null)
                 return self.Error = Error.MSPACK_ERR_ARGS;
 
             SystemImpl sys = self.System;
-            object fh = ((HeaderImpl)hdr).FileHandle;
+            object fh = (hdr as HeaderImpl)?.FileHandle;
+            if (fh == null)
+                return Error.MSPACK_ERR_ARGS;
 
             // Seek to the compressed data
             if (sys.Seek(fh, hdr.DataOffset, SeekMode.MSPACK_SYS_SEEK_START))
@@ -405,7 +407,7 @@ namespace LibMSPackSharp.KWAJ
         /// </summary>
         public static Error Decompress(Decompressor d, string input, string output)
         {
-            DecompressorImpl self = (DecompressorImpl)d;
+            DecompressorImpl self = d as DecompressorImpl;
             if (self == null)
                 return Error.MSPACK_ERR_ARGS;
 
@@ -427,7 +429,7 @@ namespace LibMSPackSharp.KWAJ
         /// </summary>
         public static Error LastError(Decompressor d)
         {
-            DecompressorImpl self = (DecompressorImpl)d;
+            DecompressorImpl self = d as DecompressorImpl;
             return (self != null) ? self.Error : Error.MSPACK_ERR_ARGS;
         }
 
diff --git a/BurnOutSharp/External/libmspack/Library.cs b/BurnOutSharp/External/libmspack/Library.cs
index 31b5ed33..f24e5c80 100644
--- a/BurnOutSharp/External/libmspack/Library.cs
+++ b/BurnOutSharp/External/libmspack/Library.cs
@@ -196,7 +196,7 @@ namespace LibMSPackSharp
         /// <param name="d">the <see cref="CAB.Decompressor"/> to destroy</param>
         public static void DestroyCABDecompressor(CAB.Decompressor d)
         {
-            CAB.DecompressorImpl self = (CAB.DecompressorImpl)d;
+            CAB.DecompressorImpl self = d as CAB.DecompressorImpl;
             if (self != null)
             {
                 SystemImpl sys = self.System;
@@ -269,7 +269,7 @@ namespace LibMSPackSharp
         /// <param name="d">the <see cref="CHM.Decompressor"/> to destroy</param>
         public static void DestroyCHMDecompressor(CHM.Decompressor d)
         {
-            CHM.DecompressorImpl self = (CHM.DecompressorImpl)d;
+            CHM.DecompressorImpl self = d as CHM.DecompressorImpl;
             if (self != null)
             {
                 SystemImpl sys = self.System;
@@ -429,7 +429,7 @@ namespace LibMSPackSharp
         /// <param name="d">the <see cref="SZDD.Decompressor"/> to destroy</param>
         public static void DestroySZDDDecompressor(SZDD.Decompressor d)
         {
-            SZDD.DecompressorImpl self = (SZDD.DecompressorImpl)d;
+            SZDD.DecompressorImpl self = d as SZDD.DecompressorImpl;
             if (self != null)
             {
                 SystemImpl sys = self.System;
@@ -491,7 +491,7 @@ namespace LibMSPackSharp
         /// <param name="d">the <see cref="KWAJ.Decompressor"/> to destroy</param>
         public static void DestroyKWAJDecompressor(KWAJ.Decompressor d)
         {
-            KWAJ.DecompressorImpl self = (KWAJ.DecompressorImpl)d;
+            KWAJ.DecompressorImpl self = d as KWAJ.DecompressorImpl;
             if (self != null)
             {
                 SystemImpl sys = self.System;
@@ -551,7 +551,7 @@ namespace LibMSPackSharp
         /// <param name="d">the <see cref="OAB.Decompressor"/> to destroy</param>
         public static void DestroyOABDecompressor(OAB.Decompressor d)
         {
-            OAB.DecompressorImpl self = (OAB.DecompressorImpl)d;
+            OAB.DecompressorImpl self = d as OAB.DecompressorImpl;
             if (self != null)
             {
                 SystemImpl sys = self.System;
diff --git a/BurnOutSharp/External/libmspack/OAB/Implementation.cs b/BurnOutSharp/External/libmspack/OAB/Implementation.cs
index f0a2fb7f..b185bb4c 100644
--- a/BurnOutSharp/External/libmspack/OAB/Implementation.cs
+++ b/BurnOutSharp/External/libmspack/OAB/Implementation.cs
@@ -62,7 +62,10 @@ namespace LibMSPackSharp.OAB
 
         private static int SysRead(object baseFile, byte[] buf, int pointer, int size)
         {
-            InternalFile file = (InternalFile)baseFile;
+            InternalFile file = baseFile as InternalFile;
+            if (file == null)
+                return 0;
+
             int bytes_read;
 
             if (size > file.Available)
@@ -82,7 +85,10 @@ namespace LibMSPackSharp.OAB
 
         private static int SysWrite(object baseFile, byte[] buf, int pointer, int size)
         {
-            InternalFile file = (InternalFile)baseFile;
+            InternalFile file = baseFile as InternalFile;
+            if (file == null)
+                return 0;
+
             int bytes_written = file.OrigSys.Write(file.OrigFile, buf, pointer, size);
 
             if (bytes_written > 0)
@@ -97,7 +103,7 @@ namespace LibMSPackSharp.OAB
 
         public static Error Decompress(Decompressor d, string input, string output)
         {
-            DecompressorImpl self = (DecompressorImpl)d;
+            DecompressorImpl self = d as DecompressorImpl;
             byte[] hdrbuf = new byte[oabhead_SIZEOF];
             LZXDStream lzx = null;
             Error ret = Error.MSPACK_ERR_OK;
@@ -332,7 +338,7 @@ namespace LibMSPackSharp.OAB
 
         public static Error DecompressIncremental(Decompressor d, string input, string basePath, string output)
         {
-            DecompressorImpl self = (DecompressorImpl)d;
+            DecompressorImpl self = d as DecompressorImpl;
             byte[] hdrbuf = new byte[patchhead_SIZEOF];
             LZXDStream lzx = null;
             int window_bits;
@@ -604,7 +610,7 @@ namespace LibMSPackSharp.OAB
 
         public static Error Param(Decompressor d, Parameters param, int value)
         {
-            DecompressorImpl self = (DecompressorImpl)d;
+            DecompressorImpl self = d as DecompressorImpl;
             if (self != null && param == Parameters.MSOABD_PARAM_DECOMPBUF && value >= 16)
             {
                 // must be at least 16 bytes (patchblk_SIZEOF, oabblk_SIZEOF)
diff --git a/BurnOutSharp/External/libmspack/SZDD/Implementation.cs b/BurnOutSharp/External/libmspack/SZDD/Implementation.cs
index e9b4f4bd..c069b14e 100644
--- a/BurnOutSharp/External/libmspack/SZDD/Implementation.cs
+++ b/BurnOutSharp/External/libmspack/SZDD/Implementation.cs
@@ -27,7 +27,7 @@ namespace LibMSPackSharp.SZDD
         /// </summary>
         public static Header Open(Decompressor d, string filename)
         {
-            DecompressorImpl self = (DecompressorImpl)d;
+            DecompressorImpl self = d as DecompressorImpl;
             if (self == null)
                 return null;
 
@@ -69,10 +69,10 @@ namespace LibMSPackSharp.SZDD
         /// </summary>
         public static void Close(Decompressor d, Header hdr)
         {
-            DecompressorImpl self = (DecompressorImpl)d;
-            HeaderImpl hdr_p = (HeaderImpl)hdr;
+            DecompressorImpl self = d as DecompressorImpl;
+            HeaderImpl hdr_p = hdr as HeaderImpl;
 
-            if (self == null || self.System == null)
+            if (self?.System == null || hdr == null)
                 return;
 
             // Close the file handle associated
@@ -150,7 +150,7 @@ namespace LibMSPackSharp.SZDD
         /// </summary>
         public static Error Extract(Decompressor d, Header hdr, string filename)
         {
-            DecompressorImpl self = (DecompressorImpl)d;
+            DecompressorImpl self = d as DecompressorImpl;
             if (self == null)
                 return Error.MSPACK_ERR_ARGS;
             if (hdr == null)
@@ -158,7 +158,9 @@ namespace LibMSPackSharp.SZDD
 
             SystemImpl sys = self.System;
 
-            object fh = ((HeaderImpl)hdr).FileHandle;
+            object fh = (hdr as HeaderImpl)?.FileHandle;
+            if (fh == null)
+                return Error.MSPACK_ERR_ARGS;
 
             // Seek to the compressed data
             long dataOffset = (hdr.Format == Format.MSSZDD_FMT_NORMAL) ? 14 : 12;
@@ -195,7 +197,7 @@ namespace LibMSPackSharp.SZDD
         /// </summary>
         public static Error Decompress(Decompressor d, string input, string output)
         {
-            DecompressorImpl self = (DecompressorImpl)d;
+            DecompressorImpl self = d as DecompressorImpl;
             if (self == null)
                 return Error.MSPACK_ERR_ARGS;
 
@@ -217,7 +219,7 @@ namespace LibMSPackSharp.SZDD
         /// </summary>
         public static Error LastError(Decompressor d)
         {
-            DecompressorImpl self = (DecompressorImpl)d;
+            DecompressorImpl self = d as DecompressorImpl;
             return (self != null) ? self.Error : Error.MSPACK_ERR_ARGS;
         }
 
diff --git a/BurnOutSharp/External/libmspack/SystemImpl.cs b/BurnOutSharp/External/libmspack/SystemImpl.cs
index 26cbaa7e..dcb09f7a 100644
--- a/BurnOutSharp/External/libmspack/SystemImpl.cs
+++ b/BurnOutSharp/External/libmspack/SystemImpl.cs
@@ -261,19 +261,19 @@ namespace LibMSPackSharp
             switch (mode)
             {
                 case OpenMode.MSPACK_SYS_OPEN_READ:
-                    fileHandle.FileHandle = File.Open(filename, FileMode.Open, FileAccess.Read);
+                    fileHandle.FileHandle = File.Open(filename, FileMode.Open, FileAccess.Read, FileShare.ReadWrite);
                     break;
 
                 case OpenMode.MSPACK_SYS_OPEN_WRITE:
-                    fileHandle.FileHandle = File.Open(filename, FileMode.Open, FileAccess.Write);
+                    fileHandle.FileHandle = File.Open(filename, FileMode.OpenOrCreate, FileAccess.Write, FileShare.ReadWrite);
                     break;
 
                 case OpenMode.MSPACK_SYS_OPEN_UPDATE:
-                    fileHandle.FileHandle = File.Open(filename, FileMode.Open, FileAccess.ReadWrite);
+                    fileHandle.FileHandle = File.Open(filename, FileMode.Open, FileAccess.ReadWrite, FileShare.ReadWrite);
                     break;
 
                 case OpenMode.MSPACK_SYS_OPEN_APPEND:
-                    fileHandle.FileHandle = File.Open(filename, FileMode.Append);
+                    fileHandle.FileHandle = File.Open(filename, FileMode.Append, FileAccess.ReadWrite, FileShare.ReadWrite);
                     break;
 
                 default: