diff --git a/SabreTools.Library/DatFiles/DatFile.cs b/SabreTools.Library/DatFiles/DatFile.cs
index 214ccfc7..e6d259f1 100644
--- a/SabreTools.Library/DatFiles/DatFile.cs
+++ b/SabreTools.Library/DatFiles/DatFile.cs
@@ -480,6 +480,7 @@ namespace SabreTools.Library.DatFiles
                 Field.Writable,
                 Field.Optional,
                 Field.Status,
+                Field.Inverted,
 
                 Field.CRC,
                 Field.MD5,
@@ -682,6 +683,12 @@ namespace SabreTools.Library.DatFiles
                                         rom.ItemStatus = romDupe.ItemStatus;
                                 }
 
+                                if (updateFields.Contains(Field.Inverted))
+                                {
+                                     if (newDatItem.ItemType == ItemType.Rom)
+                                        rom.Inverted = romDupe.Inverted;
+                                }
+
                                 #endregion
 
                                 #region Hash fields
diff --git a/SabreTools.Library/DatFiles/Filter.cs b/SabreTools.Library/DatFiles/Filter.cs
index 8f2f3f2c..f2c7d6da 100644
--- a/SabreTools.Library/DatFiles/Filter.cs
+++ b/SabreTools.Library/DatFiles/Filter.cs
@@ -254,6 +254,11 @@ namespace SabreTools.Library.DatFiles
         /// </summary>
         private FilterItem<string> Offset = new FilterItem<string>();
 
+        /// <summary>
+        /// Include or exclude offsets
+        /// </summary>
+        private FilterItem<bool?> Inverted = new FilterItem<bool?>();
+
         #endregion
 
         #endregion // Private instance variables
@@ -779,6 +784,13 @@ namespace SabreTools.Library.DatFiles
                         Offset.PositiveSet.Add(value);
                     break;
 
+                case Field.Inverted:
+                    if (negate || value.Equals("false", StringComparison.OrdinalIgnoreCase))
+                        Inverted.Neutral = false;
+                    else
+                        Inverted.Neutral = true;
+                    break;
+
                     #endregion
             }
         }
@@ -1318,6 +1330,10 @@ namespace SabreTools.Library.DatFiles
                     if (this.Optional.MatchesNeutral(null, rom.Optional) == false)
                         return false;
 
+                    // Filter on inverted
+                    if (this.Inverted.MatchesNeutral(null, rom.Inverted) == false)
+                        return false;
+
                     break;
 
                 case ItemType.Sample:
@@ -2268,6 +2284,11 @@ namespace SabreTools.Library.DatFiles
                             if (item.ItemType == ItemType.Rom)
                                 (item as Rom).Offset = null;
                         }
+                        if (field == Field.Inverted)
+                        {
+                            if (item.ItemType == ItemType.Rom)
+                                (item as Rom).Inverted = null;
+                        }
                     }                    
 
                     items[j] = item;
diff --git a/SabreTools.Library/DatFiles/Json.cs b/SabreTools.Library/DatFiles/Json.cs
index 0a763558..3b48c092 100644
--- a/SabreTools.Library/DatFiles/Json.cs
+++ b/SabreTools.Library/DatFiles/Json.cs
@@ -492,7 +492,8 @@ namespace SabreTools.Library.DatFiles
             // Prepare internal variables
             bool? def = null,
                 writable = null,
-                optional = null;
+                optional = null,
+                inverted = null;
             long size = -1;
             long? areaSize = null;
             string name = null,
@@ -588,6 +589,7 @@ namespace SabreTools.Library.DatFiles
                         (datItem as Rom).Date = date;
                         (datItem as Rom).ItemStatus = itemStatus ?? ItemStatus.None;
                         (datItem as Rom).Optional = optional;
+                        (datItem as Rom).Inverted = inverted;
                     }
 
                     ParseAddHelper(datItem);
@@ -733,6 +735,10 @@ namespace SabreTools.Library.DatFiles
                         bios = jtr.ReadAsString();
                         break;
 
+                    case "inverted":
+                        inverted = jtr.ReadAsBoolean();
+                        break;
+
                     default:
                         break;
                 }
@@ -1408,6 +1414,11 @@ namespace SabreTools.Library.DatFiles
                             jtw.WritePropertyName("optional");
                             jtw.WriteValue(rom.Optional);
                         }
+                        if (!string.IsNullOrWhiteSpace(rom.GetField(Field.Inverted, Header.ExcludeFields)))
+                        {
+                            jtw.WritePropertyName("inverted");
+                            jtw.WriteValue(rom.Inverted);
+                        }
                         break;
 
                     case ItemType.Sample:
diff --git a/SabreTools.Library/DatFiles/Logiqx.cs b/SabreTools.Library/DatFiles/Logiqx.cs
index 3f2c9805..297e5643 100644
--- a/SabreTools.Library/DatFiles/Logiqx.cs
+++ b/SabreTools.Library/DatFiles/Logiqx.cs
@@ -447,6 +447,7 @@ namespace SabreTools.Library.DatFiles
                             MergeTag = reader.GetAttribute("merge"),
                             ItemStatus = reader.GetAttribute("status").AsItemStatus(),
                             Date = Sanitizer.CleanDate(reader.GetAttribute("date")),
+                            Inverted = reader.GetAttribute("inverted").AsYesNo(),
 
                             IndexId = indexId,
                             IndexSource = filename,
@@ -1033,6 +1034,8 @@ namespace SabreTools.Library.DatFiles
                             xtw.WriteAttributeString("date", rom.Date);
                         if (!Header.ExcludeFields.Contains(Field.Status) && rom.ItemStatus != ItemStatus.None)
                             xtw.WriteAttributeString("status", rom.ItemStatus.ToString().ToLowerInvariant());
+                        if (!Header.ExcludeFields.Contains(Field.Inverted) && rom.Inverted != null)
+                            xtw.WriteAttributeString("inverted", rom.Inverted.ToString().ToLowerInvariant());
                         xtw.WriteEndElement();
                         break;
 
diff --git a/SabreTools.Library/DatFiles/SeparatedValue.cs b/SabreTools.Library/DatFiles/SeparatedValue.cs
index 21f2b2f5..76d35f0a 100644
--- a/SabreTools.Library/DatFiles/SeparatedValue.cs
+++ b/SabreTools.Library/DatFiles/SeparatedValue.cs
@@ -80,7 +80,8 @@ namespace SabreTools.Library.DatFiles
 
                 bool? def = null,
                     writable = null,
-                    optional = null;
+                    optional = null,
+                    inverted = null;
                 string name = null,
                     partName = null,
                     partInterface = null,
@@ -410,6 +411,10 @@ namespace SabreTools.Library.DatFiles
                             offset = string.IsNullOrWhiteSpace(value) ? offset : value;
                             break;
 
+                        case "DatItem.Inverted":
+                            offset = string.IsNullOrWhiteSpace(value) ? inverted : value;
+                            break;
+
                         #endregion
 
                         case "INVALID":
@@ -544,6 +549,7 @@ namespace SabreTools.Library.DatFiles
                             Date = date,
                             ItemStatus = status,
                             Optional = optional,
+                            Inverted = inverted,
 
                             IndexId = indexId,
                             IndexSource = filename,
@@ -844,6 +850,9 @@ namespace SabreTools.Library.DatFiles
                 case "offset":
                     return "DatItem.Offset";
 
+                case "inverted":
+                    return "DatItem.Inverted";
+
                 #endregion
 
                 default:
diff --git a/SabreTools.Library/DatItems/DatItem.cs b/SabreTools.Library/DatItems/DatItem.cs
index 2411722c..cd343983 100644
--- a/SabreTools.Library/DatItems/DatItem.cs
+++ b/SabreTools.Library/DatItems/DatItem.cs
@@ -810,6 +810,10 @@ namespace SabreTools.Library.DatItems
                     if (ItemType == ItemType.Rom)
                         fieldValue = (this as Rom).Offset;
                     break;
+                case Field.Inverted:
+                    if (ItemType == ItemType.Rom)
+                        fieldValue = (this as Rom).Inverted?.ToString();
+                    break;
 
                 case Field.NULL:
                 default:
diff --git a/SabreTools.Library/DatItems/Rom.cs b/SabreTools.Library/DatItems/Rom.cs
index dd5d8752..9be93b55 100644
--- a/SabreTools.Library/DatItems/Rom.cs
+++ b/SabreTools.Library/DatItems/Rom.cs
@@ -148,6 +148,12 @@ namespace SabreTools.Library.DatItems
         [JsonProperty("optional")]
         public bool? Optional { get; set; }
 
+        /// <summary>
+        /// Determine if the CRC32 hash is inverted
+        /// </summary>
+        [JsonProperty("inverted")]
+        public bool? Inverted { get; set; }
+
         #endregion
 
         #region Constructors
diff --git a/SabreTools.Library/Data/Enums.cs b/SabreTools.Library/Data/Enums.cs
index 42a4e3e9..a7f06aea 100644
--- a/SabreTools.Library/Data/Enums.cs
+++ b/SabreTools.Library/Data/Enums.cs
@@ -408,6 +408,7 @@
         Size,
         CRC,
         Offset,
+        Inverted,
     }
 
     /// <summary>
diff --git a/SabreTools.Library/Tools/Converters.cs b/SabreTools.Library/Tools/Converters.cs
index 14fcde20..02db62bc 100644
--- a/SabreTools.Library/Tools/Converters.cs
+++ b/SabreTools.Library/Tools/Converters.cs
@@ -182,6 +182,8 @@ namespace SabreTools.Library.Tools
                     return Field.Index;
                 case "infos":
                     return Field.Infos;
+                case "inverted":
+                    return Field.Inverted;
                 case "itemname":
                 case "item-name":
                 case "name":
@@ -561,8 +563,10 @@ namespace SabreTools.Library.Tools
             switch (yesno?.ToLowerInvariant())
             {
                 case "yes":
+                case "true":
                     return true;
                 case "no":
+                case "false":
                     return false;
                 case "partial":
                 default:
@@ -572,7 +576,9 @@ namespace SabreTools.Library.Tools
             return yesno?.ToLowerInvariant() switch
             {
                 "yes" => true,
+                "true" => true,
                 "no" => false,
+                "false" => false,
                 "partial" => null,
                 _ => null,
             };