diff --git a/Penumbra/Import/Textures/TexFileParser.cs b/Penumbra/Import/Textures/TexFileParser.cs
index 09025b61..ae4a39c0 100644
--- a/Penumbra/Import/Textures/TexFileParser.cs
+++ b/Penumbra/Import/Textures/TexFileParser.cs
@@ -79,8 +79,8 @@ public static class TexFileParser
         w.Write(header.Width);
         w.Write(header.Height);
         w.Write(header.Depth);
-        w.Write(header.MipCount);
-        w.Write(header.MipUnknownFlag); // TODO Lumina Update
+        w.Write((byte)(header.MipCount | (header.MipUnknownFlag ? 0x80 : 0)));
+        w.Write(header.ArraySize);
         unsafe
         {
             w.Write(header.LodOffset[0]);
diff --git a/Penumbra/UI/Tabs/Debug/DebugTab.cs b/Penumbra/UI/Tabs/Debug/DebugTab.cs
index be92b94e..4966dd64 100644
--- a/Penumbra/UI/Tabs/Debug/DebugTab.cs
+++ b/Penumbra/UI/Tabs/Debug/DebugTab.cs
@@ -15,7 +15,6 @@ using Microsoft.Extensions.DependencyInjection;
 using OtterGui;
 using OtterGui.Classes;
 using OtterGui.Services;
-using OtterGui.Text;
 using OtterGui.Widgets;
 using Penumbra.Api;
 using Penumbra.Collections.Manager;
@@ -96,6 +95,7 @@ public class DebugTab : Window, ITab, IUiService
     private readonly IClientState              _clientState;
     private readonly IpcTester                 _ipcTester;
     private readonly CrashHandlerPanel         _crashHandlerPanel;
+    private readonly TexHeaderDrawer           _texHeaderDrawer;
 
     public DebugTab(PerformanceTracker performance, Configuration config, CollectionManager collectionManager, ObjectManager objects,
         IClientState clientState,
@@ -105,7 +105,7 @@ public class DebugTab : Window, ITab, IUiService
         DrawObjectState drawObjectState, PathState pathState, SubfileHelper subfileHelper, IdentifiedCollectionCache identifiedCollectionCache,
         CutsceneService cutsceneService, ModImportManager modImporter, ImportPopup importPopup, FrameworkManager framework,
         TextureManager textureManager, ShaderReplacementFixer shaderReplacementFixer, RedrawService redraws, DictEmote emotes,
-        Diagnostics diagnostics, IpcTester ipcTester, CrashHandlerPanel crashHandlerPanel)
+        Diagnostics diagnostics, IpcTester ipcTester, CrashHandlerPanel crashHandlerPanel, TexHeaderDrawer texHeaderDrawer)
         : base("Penumbra Debug Window", ImGuiWindowFlags.NoCollapse)
     {
         IsOpen = true;
@@ -141,6 +141,7 @@ public class DebugTab : Window, ITab, IUiService
         _diagnostics               = diagnostics;
         _ipcTester                 = ipcTester;
         _crashHandlerPanel         = crashHandlerPanel;
+        _texHeaderDrawer           = texHeaderDrawer;
         _objects                   = objects;
         _clientState               = clientState;
     }
@@ -176,6 +177,8 @@ public class DebugTab : Window, ITab, IUiService
         ImGui.NewLine();
         DrawCollectionCaches();
         ImGui.NewLine();
+        _texHeaderDrawer.Draw();
+        ImGui.NewLine();
         DrawDebugCharacterUtility();
         ImGui.NewLine();
         DrawShaderReplacementFixer();
diff --git a/Penumbra/UI/Tabs/Debug/TexHeaderDrawer.cs b/Penumbra/UI/Tabs/Debug/TexHeaderDrawer.cs
new file mode 100644
index 00000000..08d51184
--- /dev/null
+++ b/Penumbra/UI/Tabs/Debug/TexHeaderDrawer.cs
@@ -0,0 +1,117 @@
+using Dalamud.Interface.DragDrop;
+using Dalamud.Interface.Utility.Raii;
+using ImGuiNET;
+using Lumina.Data.Files;
+using OtterGui.Services;
+using OtterGui.Text;
+using Penumbra.UI.Classes;
+
+namespace Penumbra.UI.Tabs.Debug;
+
+public class TexHeaderDrawer(IDragDropManager dragDrop) : IUiService
+{
+    private string?           _path;
+    private TexFile.TexHeader _header;
+    private byte[]?           _tex;
+    private Exception?        _exception;
+
+    public void Draw()
+    {
+        using var header = ImUtf8.CollapsingHeaderId("Tex Header"u8);
+        if (!header)
+            return;
+
+        DrawDragDrop();
+        DrawData();
+    }
+
+    private void DrawDragDrop()
+    {
+        dragDrop.CreateImGuiSource("TexFileDragDrop", m => m.Files.Count == 1 && m.Extensions.Contains(".tex"), m =>
+        {
+            ImUtf8.Text($"Dragging {m.Files[0]}...");
+            return true;
+        });
+
+        ImUtf8.Button("Drag .tex here...");
+        if (dragDrop.CreateImGuiTarget("TexFileDragDrop", out var files, out _))
+            ReadTex(files[0]);
+    }
+
+    private void DrawData()
+    {
+        if (_path == null)
+            return;
+
+        ImUtf8.TextFramed(_path, 0, borderColor: 0xFFFFFFFF);
+
+
+        if (_exception != null)
+        {
+            using var color = ImRaii.PushColor(ImGuiCol.Text, Colors.RegexWarningBorder);
+            ImUtf8.TextWrapped($"Failure to load file:\n{_exception}");
+        }
+        else if (_tex != null)
+        {
+            using var table = ImRaii.Table("table", 2, ImGuiTableFlags.SizingFixedFit | ImGuiTableFlags.RowBg);
+            if (!table)
+                return;
+
+            TableLine("Format"u8,     _header.Format);
+            TableLine("Width"u8,      _header.Width);
+            TableLine("Height"u8,     _header.Height);
+            TableLine("Depth"u8,      _header.Depth);
+            TableLine("Mip Levels"u8, _header.MipCount);
+            TableLine("Array Size"u8, _header.ArraySize);
+            TableLine("Type"u8,       _header.Type);
+            TableLine("Mip Flag"u8,   _header.MipUnknownFlag);
+            TableLine("Byte Size"u8,  _tex.Length);
+            unsafe
+            {
+                TableLine("LoD Offset 0"u8,  _header.LodOffset[0]);
+                TableLine("LoD Offset 1"u8,  _header.LodOffset[1]);
+                TableLine("LoD Offset 2"u8,  _header.LodOffset[2]);
+                TableLine("LoD Offset 0"u8,  _header.OffsetToSurface[0]);
+                TableLine("LoD Offset 1"u8,  _header.OffsetToSurface[1]);
+                TableLine("LoD Offset 2"u8,  _header.OffsetToSurface[2]);
+                TableLine("LoD Offset 3"u8,  _header.OffsetToSurface[3]);
+                TableLine("LoD Offset 4"u8,  _header.OffsetToSurface[4]);
+                TableLine("LoD Offset 5"u8,  _header.OffsetToSurface[5]);
+                TableLine("LoD Offset 6"u8,  _header.OffsetToSurface[6]);
+                TableLine("LoD Offset 7"u8,  _header.OffsetToSurface[7]);
+                TableLine("LoD Offset 8"u8,  _header.OffsetToSurface[8]);
+                TableLine("LoD Offset 9"u8,  _header.OffsetToSurface[9]);
+                TableLine("LoD Offset 10"u8, _header.OffsetToSurface[10]);
+                TableLine("LoD Offset 11"u8, _header.OffsetToSurface[11]);
+                TableLine("LoD Offset 12"u8, _header.OffsetToSurface[12]);
+            }
+        }
+    }
+
+    private static void TableLine<T>(ReadOnlySpan<byte> text, T value)
+    {
+        ImGui.TableNextColumn();
+        ImUtf8.Text(text);
+        ImGui.TableNextColumn();
+        ImUtf8.Text($"{value}");
+    }
+
+    private unsafe void ReadTex(string path)
+    {
+        try
+        {
+            _path = path;
+            _tex  = File.ReadAllBytes(_path);
+            if (_tex.Length < sizeof(TexFile.TexHeader))
+                throw new Exception($"Size {_tex.Length} does not include a header.");
+
+            _header    = MemoryMarshal.Read<TexFile.TexHeader>(_tex);
+            _exception = null;
+        }
+        catch (Exception ex)
+        {
+            _tex       = null;
+            _exception = ex;
+        }
+    }
+}
diff --git a/Penumbra/UI/Tabs/EffectiveTab.cs b/Penumbra/UI/Tabs/EffectiveTab.cs
index 1b9af75c..e0cab43f 100644
--- a/Penumbra/UI/Tabs/EffectiveTab.cs
+++ b/Penumbra/UI/Tabs/EffectiveTab.cs
@@ -26,7 +26,7 @@ public class EffectiveTab(CollectionManager collectionManager, CollectionSelectH
         SetupEffectiveSizes();
         collectionHeader.Draw(true);
         DrawFilters();
-        using var child = ImRaii.Child("##EffectiveChangesTab", -Vector2.One, false);
+        using var child = ImRaii.Child("##EffectiveChangesTab", ImGui.GetContentRegionAvail(), false);
         if (!child)
             return;