diff --git a/PKHeX.Core/Saves/SAV8BS.cs b/PKHeX.Core/Saves/SAV8BS.cs
index e6ef78a03..5fce3f54b 100644
--- a/PKHeX.Core/Saves/SAV8BS.cs
+++ b/PKHeX.Core/Saves/SAV8BS.cs
@@ -42,12 +42,12 @@ public SAV8BS(byte[] data, bool exportable = true) : base(data, exportable)
             // SaveBallDecoData CapsuleData[99], AffixSealData[20]
             SealList = new SealList8b(this, 0x93E0C); // size: 0x960 SaveSealData[200]
             // _RANDOM_GROUP
-            // FIeldGimmickSaveData; int[3] gearRotate
+            // FieldGimmickSaveData; int[3] gearRotate
             BerryTrees = new BerryTreeGrowSave8b(this, 0x94DA8); // size: 0x808
             Poffins = new PoffinSaveData8b(this, 0x955B0); // size: 0x644
             BattleTower = new BattleTowerWork8b(this, 0x95BF4); // size: 0x1B8
-            System = new SystemData8b(this, 0x95DAC);
-            Poketch = new Poketch8b(this, 0); // todo
+            System = new SystemData8b(this, 0x95DAC); // size: 0x138
+            Poketch = new Poketch8b(this, 0x95EE4); // todo
             Daycare = new Daycare8b(this, 0x96080); // 0x2C0
             // 0x96340 - _DENDOU_SAVEDATA; DENDOU_RECORD[30], POKEMON_DATA_INSIDE[6], ushort[4] ?
             // BadgeSaveData; byte[8]
diff --git a/PKHeX.Core/Saves/Substructures/Gen8/BS/Poketch8b.cs b/PKHeX.Core/Saves/Substructures/Gen8/BS/Poketch8b.cs
index deb731cea..2a6695079 100644
--- a/PKHeX.Core/Saves/Substructures/Gen8/BS/Poketch8b.cs
+++ b/PKHeX.Core/Saves/Substructures/Gen8/BS/Poketch8b.cs
@@ -5,7 +5,7 @@ namespace PKHeX.Core
     /// <summary>
     /// Details about the Poketch corner app.
     /// </summary>
-    /// <remarks>size: ???</remarks>
+    /// <remarks>size: 0x19C</remarks>
     [TypeConverter(typeof(ExpandableObjectConverter))]
     public sealed class Poketch8b : SaveBlock
     {
diff --git a/PKHeX.Core/Saves/Substructures/Gen8/BS/SystemData8b.cs b/PKHeX.Core/Saves/Substructures/Gen8/BS/SystemData8b.cs
index d86e0ba38..acdbee189 100644
--- a/PKHeX.Core/Saves/Substructures/Gen8/BS/SystemData8b.cs
+++ b/PKHeX.Core/Saves/Substructures/Gen8/BS/SystemData8b.cs
@@ -6,7 +6,7 @@ namespace PKHeX.Core
     /// <summary>
     /// Details about the Console and specific timestamps.
     /// </summary>
-    /// <remarks>size: ???</remarks>
+    /// <remarks>size: 0x138</remarks>
     [TypeConverter(typeof(ExpandableObjectConverter))]
     public sealed class SystemData8b : SaveBlock
     {
@@ -15,10 +15,16 @@ public sealed class SystemData8b : SaveBlock
         // (u32 count, u64 FILETIME) Latest Save Time
         // (u32 count, u64 FILETIME) Penalty Timeout Time
         // (u32 count, u64 FILETIME) Last Daily Event Time
-        // byte[???] Snapshot
+        // byte[208] ClockSnapshot (char[0x24])
         // u32 "fd_bgmEvnet"
         // s64[6] reserved
         private const int SIZE_GMTIME = 12;
+        private const int SIZE_SNAPSHOT = 0xD0;
+
+        private const int OFS_SNAPSHOT = 4 + (3 * SIZE_GMTIME) + SIZE_GMTIME; // 0x34
+        private const int OFS_FDBGM = OFS_SNAPSHOT + SIZE_SNAPSHOT;
+        private const int OFS_RESERVED = OFS_FDBGM + 4;
+        private const int SIZE_TOTAL = OFS_RESERVED + (6 * 8); // 0x138
 
         public SystemData8b(SAV8BS sav, int offset) : base(sav) => Offset = offset;