diff --git a/PKHeX.Core/Saves/SAV3.cs b/PKHeX.Core/Saves/SAV3.cs
index ecc87b4d6..dd17f5942 100644
--- a/PKHeX.Core/Saves/SAV3.cs
+++ b/PKHeX.Core/Saves/SAV3.cs
@@ -219,9 +219,10 @@ protected override void SetChecksums()
         {
             for (int i = 0; i < BLOCK_COUNT; i++)
             {
-                byte[] chunk = Data.Skip(ABO + i*SIZE_BLOCK).Take(chunkLength[BlockOrder[i]]).ToArray();
-                ushort chk = SaveUtil.CRC32(chunk);
-                BitConverter.GetBytes(chk).CopyTo(Data, ABO + i*SIZE_BLOCK + 0xFF6);
+                int ofs = ABO + i * SIZE_BLOCK;
+                int len = chunkLength[BlockOrder[i]];
+                ushort chk = SaveUtil.CRC32(Data, ofs, len);
+                BitConverter.GetBytes(chk).CopyTo(Data, ofs + 0xFF6);
             }
         }
         public override bool ChecksumsValid
@@ -230,9 +231,10 @@ public override bool ChecksumsValid
             {
                 for (int i = 0; i < BLOCK_COUNT; i++)
                 {
-                    byte[] chunk = Data.Skip(ABO + i * SIZE_BLOCK).Take(chunkLength[BlockOrder[i]]).ToArray();
-                    ushort chk = SaveUtil.CRC32(chunk);
-                    if (chk != BitConverter.ToUInt16(Data, ABO + i*SIZE_BLOCK + 0xFF6))
+                    int ofs = ABO + i * SIZE_BLOCK;
+                    int len = chunkLength[BlockOrder[i]];
+                    ushort chk = SaveUtil.CRC32(Data, ofs, len);
+                    if (chk != BitConverter.ToUInt16(Data, ofs + 0xFF6))
                         return false;
                 }
                 return true;
@@ -245,10 +247,10 @@ public override string ChecksumInfo
                 var list = new List<string>();
                 for (int i = 0; i < BLOCK_COUNT; i++)
                 {
-                    byte[] chunk = Data.Skip(ABO + i * SIZE_BLOCK).Take(chunkLength[BlockOrder[i]]).ToArray();
-                    ushort chk = SaveUtil.CRC32(chunk);
-                    ushort old = BitConverter.ToUInt16(Data, ABO + i*SIZE_BLOCK + 0xFF6);
-                    if (chk != old)
+                    int ofs = ABO + i * SIZE_BLOCK;
+                    int len = chunkLength[BlockOrder[i]];
+                    ushort chk = SaveUtil.CRC32(Data, ofs, len);
+                    if (chk != BitConverter.ToUInt16(Data, ofs + 0xFF6))
                         list.Add($"Block {BlockOrder[i]:00} @ {i*SIZE_BLOCK:X5} invalid.");
                 }
                 return list.Any() ? string.Join(Environment.NewLine, list) : "Checksums are valid.";
diff --git a/PKHeX.Core/Saves/SaveUtil.cs b/PKHeX.Core/Saves/SaveUtil.cs
index 011b8f29a..200e79e45 100644
--- a/PKHeX.Core/Saves/SaveUtil.cs
+++ b/PKHeX.Core/Saves/SaveUtil.cs
@@ -647,20 +647,33 @@ public static ushort CRC16(byte[] data, int start, int length, ushort initial =
                 chk = (ushort) (crc16[(data[i] ^ chk) & 0xFF] ^ chk >> 8);
             return (ushort)~chk;
         }
+        /// <summary>Calculates the 32bit checksum over an input byte array. Used in GBA save files.</summary>
+        /// <param name="data">Input byte array</param>
+        /// <param name="initial">Initial value for checksum</param>
+        /// <returns>Checksum</returns>
+        public static ushort CRC16(byte[] data, ushort initial = 0) => CRC16(data, 0, data.Length, initial);
         public static byte[] Resign7(byte[] sav7)
         {
             return MemeCrypto.Resign7(sav7);
         }
         /// <summary>Calculates the 32bit checksum over an input byte array. Used in GBA save files.</summary>
         /// <param name="data">Input byte array</param>
+        /// <param name="start">Offset to start checksum at</param>
+        /// <param name="length">Length of array to checksum</param>
+        /// <param name="initial">Initial value for checksum</param>
         /// <returns>Checksum</returns>
-        public static ushort CRC32(byte[] data)
+        public static ushort CRC32(byte[] data, int start, int length, uint initial = 0)
         {
-            uint val = 0;
-            for (int i = 0; i < data.Length; i += 4)
+            uint val = initial;
+            for (int i = start; i < start + length; i += 4)
                 val += BitConverter.ToUInt32(data, i);
             return (ushort)(val + (val >> 16));
         }
+        /// <summary>Calculates the 32bit checksum over an input byte array. Used in GBA save files.</summary>
+        /// <param name="data">Input byte array</param>
+        /// <param name="initial">Initial value for checksum</param>
+        /// <returns>Checksum</returns>
+        public static ushort CRC32(byte[] data, uint initial = 0) => CRC32(data, 0, data.Length, initial);
         private static void CheckHeaderFooter(ref byte[] input, ref byte[] header, ref byte[] footer)
         {
             if (input.Length > SIZE_G4RAW) // DeSmuME Gen4/5 DSV