diff --git a/build/CodeGen/Stage2/KeysCodeGen.cs b/build/CodeGen/Stage2/KeysCodeGen.cs
index 3b483bf3..ecb8abdf 100644
--- a/build/CodeGen/Stage2/KeysCodeGen.cs
+++ b/build/CodeGen/Stage2/KeysCodeGen.cs
@@ -11,8 +11,8 @@ namespace LibHacBuild.CodeGen.Stage2;
 
 public static class KeysCodeGen
 {
-    private static string InputMainKeyFileName = "IncludedKeys.txt";
-    private static string GeneratedFilePath = "LibHac/Common/Keys/DefaultKeySet.Generated.cs";
+    private const string InputMainKeyFileName = "IncludedKeys.txt";
+    private const string GeneratedFilePath = "LibHac/Common/Keys/DefaultKeySet.Generated.cs";
 
     public static void Run()
     {
@@ -45,6 +45,8 @@ private static string BuildDefaultKeySetFile(KeySet keySet)
         BuildArray(sb, "DerivedKeysDev", SpanHelpers.AsReadOnlyByteSpan(in keySet.KeyStruct.DerivedKeysDev));
         BuildArray(sb, "DerivedKeysProd", SpanHelpers.AsReadOnlyByteSpan(in keySet.KeyStruct.DerivedKeysProd));
         BuildArray(sb, "DeviceKeys", SpanHelpers.AsReadOnlyByteSpan(in keySet.KeyStruct.DeviceKeys));
+        BuildArray(sb, "DerivedDeviceKeysDev", SpanHelpers.AsReadOnlyByteSpan(in keySet.KeyStruct.DerivedDeviceKeysDev));
+        BuildArray(sb, "DerivedDeviceKeysProd", SpanHelpers.AsReadOnlyByteSpan(in keySet.KeyStruct.DerivedDeviceKeysProd));
         BuildArray(sb, "RsaSigningKeysDev", SpanHelpers.AsReadOnlyByteSpan(in keySet.KeyStruct.RsaSigningKeysDev));
         BuildArray(sb, "RsaSigningKeysProd", SpanHelpers.AsReadOnlyByteSpan(in keySet.KeyStruct.RsaSigningKeysProd));
         BuildArray(sb, "RsaKeys", SpanHelpers.AsReadOnlyByteSpan(in keySet.KeyStruct.RsaKeys));
diff --git a/src/LibHac/Common/Keys/DefaultKeySet.Empty.cs b/src/LibHac/Common/Keys/DefaultKeySet.Empty.cs
index cbba6f1a..944293b1 100644
--- a/src/LibHac/Common/Keys/DefaultKeySet.Empty.cs
+++ b/src/LibHac/Common/Keys/DefaultKeySet.Empty.cs
@@ -12,6 +12,8 @@ internal static partial class DefaultKeySet
     private static ReadOnlySpan<byte> DerivedKeysDev => new byte[] { };
     private static ReadOnlySpan<byte> DerivedKeysProd => new byte[] { };
     private static ReadOnlySpan<byte> DeviceKeys => new byte[] { };
+    private static ReadOnlySpan<byte> DerivedDeviceKeysDev => new byte[] { };
+    private static ReadOnlySpan<byte> DerivedDeviceKeysProd => new byte[] { };
     private static ReadOnlySpan<byte> RsaSigningKeysDev => new byte[] { };
     private static ReadOnlySpan<byte> RsaSigningKeysProd => new byte[] { };
     private static ReadOnlySpan<byte> RsaKeys => new byte[] { };
diff --git a/src/LibHac/Common/Keys/DefaultKeySet.cs b/src/LibHac/Common/Keys/DefaultKeySet.cs
index bdc2dce6..58366e6a 100644
--- a/src/LibHac/Common/Keys/DefaultKeySet.cs
+++ b/src/LibHac/Common/Keys/DefaultKeySet.cs
@@ -1,6 +1,5 @@
 using System.Collections.Generic;
 using System.Runtime.CompilerServices;
-using System.Runtime.InteropServices;
 using Type = LibHac.Common.Keys.KeyInfo.KeyType;
 
 namespace LibHac.Common.Keys;
@@ -16,59 +15,70 @@ public static KeySet CreateDefaultKeySet()
         var keySet = new KeySet();
 
         // Fill the key set with any key structs included in the library.
+        // This is split into multiple parts so the binary size isn't increased when providing only some keys.
         if (RootKeysDev.Length == Unsafe.SizeOf<RootKeys>())
         {
-            keySet.KeyStruct.RootKeysDev = MemoryMarshal.Cast<byte, RootKeys>(RootKeysDev)[0];
+            keySet.KeyStruct.RootKeysDev = SpanHelpers.AsReadOnlyStruct<RootKeys>(RootKeysDev);
         }
 
         if (RootKeysProd.Length == Unsafe.SizeOf<RootKeys>())
         {
-            keySet.KeyStruct.RootKeysProd = MemoryMarshal.Cast<byte, RootKeys>(RootKeysProd)[0];
+            keySet.KeyStruct.RootKeysProd = SpanHelpers.AsReadOnlyStruct<RootKeys>(RootKeysProd);
         }
 
         if (KeySeeds.Length == Unsafe.SizeOf<KeySeeds>())
         {
-            keySet.KeyStruct.KeySeeds = MemoryMarshal.Cast<byte, KeySeeds>(KeySeeds)[0];
+            keySet.KeyStruct.KeySeeds = SpanHelpers.AsReadOnlyStruct<KeySeeds>(KeySeeds);
         }
 
         if (StoredKeysDev.Length == Unsafe.SizeOf<StoredKeys>())
         {
-            keySet.KeyStruct.StoredKeysDev = MemoryMarshal.Cast<byte, StoredKeys>(StoredKeysDev)[0];
+            keySet.KeyStruct.StoredKeysDev = SpanHelpers.AsReadOnlyStruct<StoredKeys>(StoredKeysDev);
         }
 
         if (StoredKeysProd.Length == Unsafe.SizeOf<StoredKeys>())
         {
-            keySet.KeyStruct.StoredKeysProd = MemoryMarshal.Cast<byte, StoredKeys>(StoredKeysProd)[0];
+            keySet.KeyStruct.StoredKeysProd = SpanHelpers.AsReadOnlyStruct<StoredKeys>(StoredKeysProd);
         }
 
         if (DerivedKeysDev.Length == Unsafe.SizeOf<DerivedKeys>())
         {
-            keySet.KeyStruct.DerivedKeysDev = MemoryMarshal.Cast<byte, DerivedKeys>(DerivedKeysDev)[0];
+            keySet.KeyStruct.DerivedKeysDev = SpanHelpers.AsReadOnlyStruct<DerivedKeys>(DerivedKeysDev);
         }
 
         if (DerivedKeysProd.Length == Unsafe.SizeOf<DerivedKeys>())
         {
-            keySet.KeyStruct.DerivedKeysProd = MemoryMarshal.Cast<byte, DerivedKeys>(DerivedKeysProd)[0];
+            keySet.KeyStruct.DerivedKeysProd = SpanHelpers.AsReadOnlyStruct<DerivedKeys>(DerivedKeysProd);
         }
 
         if (DeviceKeys.Length == Unsafe.SizeOf<DeviceKeys>())
         {
-            keySet.KeyStruct.DeviceKeys = MemoryMarshal.Cast<byte, DeviceKeys>(DeviceKeys)[0];
+            keySet.KeyStruct.DeviceKeys = SpanHelpers.AsReadOnlyStruct<DeviceKeys>(DeviceKeys);
+        }
+
+        if (DerivedDeviceKeysDev.Length == Unsafe.SizeOf<DerivedDeviceKeys>())
+        {
+            keySet.KeyStruct.DerivedDeviceKeysDev = SpanHelpers.AsReadOnlyStruct<DerivedDeviceKeys>(DerivedDeviceKeysDev);
+        }
+
+        if (DerivedDeviceKeysProd.Length == Unsafe.SizeOf<DerivedDeviceKeys>())
+        {
+            keySet.KeyStruct.DerivedDeviceKeysProd = SpanHelpers.AsReadOnlyStruct<DerivedDeviceKeys>(DerivedDeviceKeysProd);
         }
 
         if (RsaSigningKeysDev.Length == Unsafe.SizeOf<RsaSigningKeys>())
         {
-            keySet.KeyStruct.RsaSigningKeysDev = MemoryMarshal.Cast<byte, RsaSigningKeys>(RsaSigningKeysDev)[0];
+            keySet.KeyStruct.RsaSigningKeysDev = SpanHelpers.AsReadOnlyStruct<RsaSigningKeys>(RsaSigningKeysDev);
         }
 
         if (RsaSigningKeysProd.Length == Unsafe.SizeOf<RsaSigningKeys>())
         {
-            keySet.KeyStruct.RsaSigningKeysProd = MemoryMarshal.Cast<byte, RsaSigningKeys>(RsaSigningKeysProd)[0];
+            keySet.KeyStruct.RsaSigningKeysProd = SpanHelpers.AsReadOnlyStruct<RsaSigningKeys>(RsaSigningKeysProd);
         }
 
         if (RsaKeys.Length == Unsafe.SizeOf<RsaKeys>())
         {
-            keySet.KeyStruct.RsaKeys = MemoryMarshal.Cast<byte, RsaKeys>(RsaKeys)[0];
+            keySet.KeyStruct.RsaKeys = SpanHelpers.AsReadOnlyStruct<RsaKeys>(RsaKeys);
         }
 
         return keySet;
diff --git a/src/LibHac/Common/Keys/KeySet.cs b/src/LibHac/Common/Keys/KeySet.cs
index a70dee9d..240d07f1 100644
--- a/src/LibHac/Common/Keys/KeySet.cs
+++ b/src/LibHac/Common/Keys/KeySet.cs
@@ -33,6 +33,7 @@ public enum Mode
     private ref RootKeys RootKeys => ref _mode == Mode.Dev ? ref _keys.RootKeysDev : ref _keys.RootKeysProd;
     private ref StoredKeys StoredKeys => ref _mode == Mode.Dev ? ref _keys.StoredKeysDev : ref _keys.StoredKeysProd;
     private ref DerivedKeys DerivedKeys => ref _mode == Mode.Dev ? ref _keys.DerivedKeysDev : ref _keys.DerivedKeysProd;
+    private ref DerivedDeviceKeys DerivedDeviceKeys => ref _mode == Mode.Dev ? ref _keys.DerivedDeviceKeysDev : ref _keys.DerivedDeviceKeysProd;
     private ref RsaSigningKeys RsaSigningKeys => ref _mode == Mode.Dev ? ref _keys.RsaSigningKeysDev : ref _keys.RsaSigningKeysProd;
     private ref RsaKeys RsaKeys => ref _keys.RsaKeys;
 
@@ -94,17 +95,18 @@ public enum Mode
 
     public ref AesKey SecureBootKey => ref _keys.DeviceKeys.SecureBootKey;
     public ref AesKey TsecKey => ref _keys.DeviceKeys.TsecKey;
-    public Span<AesKey> KeyBlobKeys => _keys.DeviceKeys.KeyBlobKeys.Items;
-    public Span<AesKey> KeyBlobMacKeys => _keys.DeviceKeys.KeyBlobMacKeys.Items;
-    public Span<EncryptedKeyBlob> EncryptedKeyBlobs => _keys.DeviceKeys.EncryptedKeyBlobs.Items;
-    public ref AesKey DeviceKey => ref _keys.DeviceKeys.DeviceKey;
-    public Span<AesXtsKey> BisKeys => _keys.DeviceKeys.BisKeys.Items;
-    public Span<AesKey> DeviceUniqueSaveMacKeys => _keys.DeviceKeys.DeviceUniqueSaveMacKeys.Items;
-    public ref AesKey SeedUniqueSaveMacKey => ref _keys.DeviceKeys.SeedUniqueSaveMacKey;
     public ref AesKey SdCardEncryptionSeed => ref _keys.DeviceKeys.SdCardEncryptionSeed;
+    public Span<EncryptedKeyBlob> EncryptedKeyBlobs => _keys.DeviceKeys.EncryptedKeyBlobs.Items;
+
+    public Span<AesKey> KeyBlobKeys => DerivedDeviceKeys.KeyBlobKeys.Items;
+    public Span<AesKey> KeyBlobMacKeys => DerivedDeviceKeys.KeyBlobMacKeys.Items;
+    public ref AesKey DeviceKey => ref DerivedDeviceKeys.DeviceKey;
+    public Span<AesXtsKey> BisKeys => DerivedDeviceKeys.BisKeys.Items;
+    public Span<AesKey> DeviceUniqueSaveMacKeys => DerivedDeviceKeys.DeviceUniqueSaveMacKeys.Items;
+    public ref AesKey SeedUniqueSaveMacKey => ref DerivedDeviceKeys.SeedUniqueSaveMacKey;
 
     // Todo: Make a separate type? Not actually an AES-XTS key, but it's still the same shape.
-    public Span<AesXtsKey> SdCardEncryptionKeys => _keys.DeviceKeys.SdCardEncryptionKeys.Items;
+    public Span<AesXtsKey> SdCardEncryptionKeys => DerivedDeviceKeys.SdCardEncryptionKeys.Items;
 
     public Span<RsaKey> NcaHeaderSigningKeys => RsaSigningKeys.NcaHeaderSigningKeys.Items;
     public Span<RsaKey> AcidSigningKeys => RsaSigningKeys.AcidSigningKeys.Items;
@@ -269,6 +271,8 @@ public struct AllKeys
     public DerivedKeys DerivedKeysDev;
     public DerivedKeys DerivedKeysProd;
     public DeviceKeys DeviceKeys;
+    public DerivedDeviceKeys DerivedDeviceKeysDev;
+    public DerivedDeviceKeys DerivedDeviceKeysProd;
     public RsaSigningKeys RsaSigningKeysDev;
     public RsaSigningKeys RsaSigningKeysProd;
     public RsaKeys RsaKeys;
@@ -354,14 +358,18 @@ public struct DeviceKeys
 {
     public AesKey SecureBootKey;
     public AesKey TsecKey;
+    public AesKey SdCardEncryptionSeed;
+    public Array32<EncryptedKeyBlob> EncryptedKeyBlobs;
+}
+
+public struct DerivedDeviceKeys
+{
     public Array32<AesKey> KeyBlobKeys;
     public Array32<AesKey> KeyBlobMacKeys;
-    public Array32<EncryptedKeyBlob> EncryptedKeyBlobs;
     public AesKey DeviceKey;
     public Array4<AesXtsKey> BisKeys;
     public Array2<AesKey> DeviceUniqueSaveMacKeys;
     public AesKey SeedUniqueSaveMacKey;
-    public AesKey SdCardEncryptionSeed;
     public Array3<AesXtsKey> SdCardEncryptionKeys;
 }