diff --git a/SabreTools.Serialization/Extensions/XZ.cs b/SabreTools.Serialization/Extensions/XZ.cs
index 5bb4e9d0..485399f8 100644
--- a/SabreTools.Serialization/Extensions/XZ.cs
+++ b/SabreTools.Serialization/Extensions/XZ.cs
@@ -1,3 +1,5 @@
+using System.Collections.Generic;
+
 namespace SabreTools.Data.Extensions
 {
     public static class XZ
@@ -17,15 +19,15 @@ namespace SabreTools.Data.Extensions
             if (maxSize > 9)
                 maxSize = 9;
 
-            ulong output = value[0] & 0x7F;
+            ulong output = (ulong)(value[0] & 0x7F);
             int i = 0;
 
-            while (value[i++] & 0x80 != 0)
+            while ((value[i++] & 0x80) != 0)
             {
                 if (i >= maxSize || value[i] == 0x00)
                     return 0;
 
-                output |= (value[i] & 0x7F) << (i * 7);
+                output |= (ulong)(value[i] & 0x7F) << (i * 7);
             }
 
             return output;
@@ -44,10 +46,9 @@ namespace SabreTools.Data.Extensions
 
             var output = new List<byte>();
 
-            int i = 0;
             while (value >= 0x80)
             {
-                output.Add((byte)value | 0x80);
+                output.Add((byte)(value | 0x80));
                 value >>= 7;
             }
 
@@ -55,4 +56,4 @@ namespace SabreTools.Data.Extensions
             return [.. output];
         }
     }
-}
\ No newline at end of file
+}
diff --git a/SabreTools.Serialization/Models/XZ/Constants.cs b/SabreTools.Serialization/Models/XZ/Constants.cs
index d8d0c5b9..4c6e4e10 100644
--- a/SabreTools.Serialization/Models/XZ/Constants.cs
+++ b/SabreTools.Serialization/Models/XZ/Constants.cs
@@ -6,4 +6,4 @@ namespace SabreTools.Data.Models.XZ
 
         public static readonly byte[] FooterSignatureBytes = [0x59, 0x5A];
     }
-}
\ No newline at end of file
+}
diff --git a/SabreTools.Serialization/Models/XZ/Record.cs b/SabreTools.Serialization/Models/XZ/Record.cs
index 1f3aab4b..f25c1944 100644
--- a/SabreTools.Serialization/Models/XZ/Record.cs
+++ b/SabreTools.Serialization/Models/XZ/Record.cs
@@ -6,7 +6,7 @@ namespace SabreTools.Data.Models.XZ
         /// Unpadded size of the block
         /// </summary>
         /// <remarks>Stored as a variable-length integer</remarks>
-        public byte UnpaddedSize { get; set; }
+        public byte[]? UnpaddedSize { get; set; }
 
         /// <summary>
         /// Uncompressed size of the block