diff --git a/SabreTools.Serialization/Models/SecuROM/AddD.cs b/SabreTools.Serialization/Models/SecuROM/AddD.cs
index 89477bf6..aafb1e7f 100644
--- a/SabreTools.Serialization/Models/SecuROM/AddD.cs
+++ b/SabreTools.Serialization/Models/SecuROM/AddD.cs
@@ -37,19 +37,26 @@
         public string? Build { get; set; }
 
         /// <summary>
-        /// Unknown (0x14h), Variable number of bytes before entry table
+        /// Unknown
+        /// </summary>
+        /// <remarks>44 bytes</remarks>
+        public byte[]? Unknown1 { get; set; }
+
+        /// <summary>
+        /// Product ID?
         /// </summary>
         /// <remarks>
-        /// 44 bytes in EXPUNGED, 3.17.00.0017, 3.17.00.0019, 4.47.00.0039
-        /// 112 bytes in 4.84.00.0054, 4.84.69.0037, 4.84.76.7966, 4.84.76.7968, 4.85.07.0009
-        /// 112 byte range contains a fixed-length string at 0x2C, possibly a product ID?
-        ///     "801400-001" in 4.84.00.0054
-        ///     "594130-001" in 4.84.69.0037
-        ///     "554900-001" in 4.84.76.7966
-        ///     "554900-001" in 4.84.76.7968
-        ///     "548520-001" in 4.85.07.0009
+        /// 10 bytes, only present in 4.84.00.0054, 4.84.69.0037, 4.84.76.7966, 4.84.76.7968, 4.85.07.0009
         /// </remarks>
-        public byte[]? Unknown { get; set; }
+        public string? ProductId { get; set; }
+
+        /// <summary>
+        /// Unknown
+        /// </summary>
+        /// <remarks>
+        /// 58 bytes, only present in 4.84.00.0054, 4.84.69.0037, 4.84.76.7966, 4.84.76.7968, 4.85.07.0009
+        /// </remarks>
+        public byte[]? Unknown2 { get; set; }
 
         /// <summary>
         /// Entry table
diff --git a/SabreTools.Serialization/Readers/SecuROMAddD.cs b/SabreTools.Serialization/Readers/SecuROMAddD.cs
index d95f1661..63c66c11 100644
--- a/SabreTools.Serialization/Readers/SecuROMAddD.cs
+++ b/SabreTools.Serialization/Readers/SecuROMAddD.cs
@@ -1,5 +1,6 @@
 using System.IO;
 using System.Text;
+using System.Text.RegularExpressions;
 using SabreTools.Data.Models.SecuROM;
 using SabreTools.IO.Extensions;
 using static SabreTools.Data.Models.SecuROM.Constants;
@@ -48,9 +49,21 @@ namespace SabreTools.Serialization.Readers
             obj.Version = data.ReadNullTerminatedAnsiString();
             byte[] buildBytes = data.ReadBytes(4);
             obj.Build = Encoding.ASCII.GetString(buildBytes);
+            obj.Unknown1 = data.ReadBytes(44);
 
-            // TODO: Figure out how to determine how many bytes are here consistently
-            obj.Unknown = data.ReadBytes(1);
+            // Peek at the next 10 bytes
+            long currentOffset = data.Position;
+            byte[] temp = data.ReadBytes(10);
+            string tempString = Encoding.ASCII.GetString(temp);
+            data.Seek(currentOffset, SeekOrigin.Begin);
+
+            // If the temp string is a regex match for an ID
+            if (Regex.IsMatch(tempString, @"[0-9]{6}-[0-9]{3}"))
+            {
+                byte[] productIdBytes = data.ReadBytes(10);
+                obj.ProductId = Encoding.ASCII.GetString(productIdBytes);
+                obj.Unknown2 = data.ReadBytes(58);
+            }
 
             obj.Entries = new AddDEntry[obj.EntryCount];
             for (int i = 0; i < obj.Entries.Length; i++)