diff --git a/UnleashedRecomp/CMakeLists.txt b/UnleashedRecomp/CMakeLists.txt
index 1a9c07e7..500bc0d5 100644
--- a/UnleashedRecomp/CMakeLists.txt
+++ b/UnleashedRecomp/CMakeLists.txt
@@ -183,6 +183,8 @@ set(UNLEASHED_RECOMP_USER_CXX_SOURCES
     "user/config.cpp"
     "user/registry.cpp"
     "user/paths.cpp"
+    "user/persistent_data.cpp"
+    "user/persistent_storage_manager.cpp"
 )
 
 set(UNLEASHED_RECOMP_MOD_CXX_SOURCES
diff --git a/UnleashedRecomp/api/SWA/System/ApplicationDocument.h b/UnleashedRecomp/api/SWA/System/ApplicationDocument.h
index 21949711..1e6ab27f 100644
--- a/UnleashedRecomp/api/SWA/System/ApplicationDocument.h
+++ b/UnleashedRecomp/api/SWA/System/ApplicationDocument.h
@@ -80,9 +80,13 @@ namespace SWA
             boost::shared_ptr<Hedgehog::Mirage::CRenderScene> m_spRenderScene;
             SWA_INSERT_PADDING(0x04);
             boost::shared_ptr<CGameParameter> m_spGameParameter;
-            SWA_INSERT_PADDING(0x78);
+            SWA_INSERT_PADDING(0x0C);
+            boost::anonymous_shared_ptr m_spItemParamManager;
+            SWA_INSERT_PADDING(0x64);
             boost::shared_ptr<Hedgehog::Base::CCriticalSection> m_spCriticalSection;
-            SWA_INSERT_PADDING(0x20);
+            SWA_INSERT_PADDING(0x14);
+            bool m_ShowDLCInfo;
+            SWA_INSERT_PADDING(0x08);
         };
 
         // TODO: Hedgehog::Base::TSynchronizedPtr<CApplicationDocument>
@@ -111,7 +115,9 @@ namespace SWA
     SWA_ASSERT_OFFSETOF(CApplicationDocument::CMember, m_Field10C, 0x10C);
     SWA_ASSERT_OFFSETOF(CApplicationDocument::CMember, m_spRenderScene, 0x12C);
     SWA_ASSERT_OFFSETOF(CApplicationDocument::CMember, m_spGameParameter, 0x138);
+    SWA_ASSERT_OFFSETOF(CApplicationDocument::CMember, m_spItemParamManager, 0x14C);
     SWA_ASSERT_OFFSETOF(CApplicationDocument::CMember, m_spCriticalSection, 0x1B8);
+    SWA_ASSERT_OFFSETOF(CApplicationDocument::CMember, m_ShowDLCInfo, 0x1D4);
     SWA_ASSERT_SIZEOF(CApplicationDocument::CMember, 0x1E0);
 
     SWA_ASSERT_OFFSETOF(CApplicationDocument, m_pMember, 0x04);
diff --git a/UnleashedRecomp/api/SWA/System/GameParameter.h b/UnleashedRecomp/api/SWA/System/GameParameter.h
index 95618144..da6b3735 100644
--- a/UnleashedRecomp/api/SWA/System/GameParameter.h
+++ b/UnleashedRecomp/api/SWA/System/GameParameter.h
@@ -7,11 +7,19 @@ namespace SWA
     class CGameParameter // : public Hedgehog::Universe::CMessageActor
     {
     public:
-        struct SSaveData;
+        struct SSaveData
+        {
+            SWA_INSERT_PADDING(0x8600);
+            be<uint32_t> DLCFlags[8];
+            SWA_INSERT_PADDING(0x15C);
+        };
+
         struct SStageParameter;
 
         SWA_INSERT_PADDING(0x94);
         xpointer<SSaveData> m_pSaveData;
         xpointer<SStageParameter> m_pStageParameter;
     };
+
+    SWA_ASSERT_OFFSETOF(CGameParameter::SSaveData, DLCFlags, 0x8600);
 }
diff --git a/UnleashedRecomp/hid/driver/sdl_hid.cpp b/UnleashedRecomp/hid/driver/sdl_hid.cpp
index 85e6793a..7220abbe 100644
--- a/UnleashedRecomp/hid/driver/sdl_hid.cpp
+++ b/UnleashedRecomp/hid/driver/sdl_hid.cpp
@@ -310,6 +310,8 @@ void hid::Init()
     SDL_SetHint(SDL_HINT_JOYSTICK_HIDAPI_PS5_RUMBLE, "1");
     SDL_SetHint(SDL_HINT_JOYSTICK_HIDAPI_WII, "1");
     SDL_SetHint(SDL_HINT_XINPUT_ENABLED, "1");
+    
+    SDL_SetHint(SDL_HINT_GAMECONTROLLER_USE_BUTTON_LABELS, "0"); // Uses Button Labels. This hint is disabled for Nintendo Controllers.
 
     SDL_InitSubSystem(SDL_INIT_EVENTS);
     SDL_AddEventWatch(HID_OnSDLEvent, nullptr);
diff --git a/UnleashedRecomp/install/installer.cpp b/UnleashedRecomp/install/installer.cpp
index 9574c5d5..774a141e 100644
--- a/UnleashedRecomp/install/installer.cpp
+++ b/UnleashedRecomp/install/installer.cpp
@@ -67,6 +67,73 @@ static std::unique_ptr<VirtualFileSystem> createFileSystemFromPath(const std::fi
     }
 }
 
+static bool checkFile(const FilePair &pair, const uint64_t *fileHashes, const std::filesystem::path &targetDirectory, std::vector<uint8_t> &fileData, Journal &journal, const std::function<bool()> &progressCallback, bool checkSizeOnly) {
+    const std::string fileName(pair.first);
+    const uint32_t hashCount = pair.second;
+    const std::filesystem::path filePath = targetDirectory / fileName;
+    if (!std::filesystem::exists(filePath))
+    {
+        journal.lastResult = Journal::Result::FileMissing;
+        journal.lastErrorMessage = fmt::format("File {} does not exist.", fileName);
+        return false;
+    }
+
+    std::error_code ec;
+    size_t fileSize = std::filesystem::file_size(filePath, ec);
+    if (ec)
+    {
+        journal.lastResult = Journal::Result::FileReadFailed;
+        journal.lastErrorMessage = fmt::format("Failed to read file size for {}.", fileName);
+        return false;
+    }
+
+    if (checkSizeOnly)
+    {
+        journal.progressTotal += fileSize;
+    }
+    else
+    {
+        std::ifstream fileStream(filePath, std::ios::binary);
+        if (fileStream.is_open())
+        {
+            fileData.resize(fileSize);
+            fileStream.read((char *)(fileData.data()), fileSize);
+        }
+
+        if (!fileStream.is_open() || fileStream.bad())
+        {
+            journal.lastResult = Journal::Result::FileReadFailed;
+            journal.lastErrorMessage = fmt::format("Failed to read file {}.", fileName);
+            return false;
+        }
+
+        uint64_t fileHash = XXH3_64bits(fileData.data(), fileSize);
+        bool fileHashFound = false;
+        for (uint32_t i = 0; i < hashCount && !fileHashFound; i++)
+        {
+            fileHashFound = fileHash == fileHashes[i];
+        }
+
+        if (!fileHashFound)
+        {
+            journal.lastResult = Journal::Result::FileHashFailed;
+            journal.lastErrorMessage = fmt::format("File {} did not match any of the known hashes.", fileName);
+            return false;
+        }
+
+        journal.progressCounter += fileSize;
+    }
+
+    if (!progressCallback())
+    {
+        journal.lastResult = Journal::Result::Cancelled;
+        journal.lastErrorMessage = "Check was cancelled.";
+        return false;
+    }
+
+    return true;
+}
+
 static bool copyFile(const FilePair &pair, const uint64_t *fileHashes, VirtualFileSystem &sourceVfs, const std::filesystem::path &targetDirectory, bool skipHashChecks, std::vector<uint8_t> &fileData, Journal &journal, const std::function<bool()> &progressCallback) {
     const std::string filename(pair.first);
     const uint32_t hashCount = pair.second;
@@ -204,6 +271,45 @@ static DLC detectDLC(const std::filesystem::path &sourcePath, VirtualFileSystem
     }
 }
 
+static bool fillDLCSource(DLC dlc, Installer::DLCSource &dlcSource) 
+{
+    switch (dlc)
+    {
+    case DLC::Spagonia:
+        dlcSource.filePairs = { SpagoniaFiles, SpagoniaFilesSize };
+        dlcSource.fileHashes = SpagoniaHashes;
+        dlcSource.targetSubDirectory = SpagoniaDirectory;
+        return true;
+    case DLC::Chunnan:
+        dlcSource.filePairs = { ChunnanFiles, ChunnanFilesSize };
+        dlcSource.fileHashes = ChunnanHashes;
+        dlcSource.targetSubDirectory = ChunnanDirectory;
+        return true;
+    case DLC::Mazuri:
+        dlcSource.filePairs = { MazuriFiles, MazuriFilesSize };
+        dlcSource.fileHashes = MazuriHashes;
+        dlcSource.targetSubDirectory = MazuriDirectory;
+        return true;
+    case DLC::Holoska:
+        dlcSource.filePairs = { HoloskaFiles, HoloskaFilesSize };
+        dlcSource.fileHashes = HoloskaHashes;
+        dlcSource.targetSubDirectory = HoloskaDirectory;
+        return true;
+    case DLC::ApotosShamar:
+        dlcSource.filePairs = { ApotosShamarFiles, ApotosShamarFilesSize };
+        dlcSource.fileHashes = ApotosShamarHashes;
+        dlcSource.targetSubDirectory = ApotosShamarDirectory;
+        return true;
+    case DLC::EmpireCityAdabat:
+        dlcSource.filePairs = { EmpireCityAdabatFiles, EmpireCityAdabatFilesSize };
+        dlcSource.fileHashes = EmpireCityAdabatHashes;
+        dlcSource.targetSubDirectory = EmpireCityAdabatDirectory;
+        return true;
+    default:
+        return false;
+    }
+}
+
 bool Installer::checkGameInstall(const std::filesystem::path &baseDirectory, std::filesystem::path &modulePath)
 {
     modulePath = baseDirectory / PatchedDirectory / GameExecutableFile;
@@ -254,6 +360,40 @@ bool Installer::checkAllDLC(const std::filesystem::path& baseDirectory)
     return result;
 }
 
+bool Installer::checkInstallIntegrity(const std::filesystem::path &baseDirectory, Journal &journal, const std::function<bool()> &progressCallback)
+{
+    // Run the file checks twice: once to fill out the progress counter and the file sizes, and another pass to do the hash integrity checks.
+    for (uint32_t checkPass = 0; checkPass < 2; checkPass++)
+    {
+        bool checkSizeOnly = (checkPass == 0);
+        if (!checkFiles({ GameFiles, GameFilesSize }, GameHashes, baseDirectory / GameDirectory, journal, progressCallback, checkSizeOnly))
+        {
+            return false;
+        }
+
+        if (!checkFiles({ UpdateFiles, UpdateFilesSize }, UpdateHashes, baseDirectory / UpdateDirectory, journal, progressCallback, checkSizeOnly))
+        {
+            return false;
+        }
+
+        for (int i = 1; i < (int)DLC::Count; i++)
+        {
+            if (checkDLCInstall(baseDirectory, (DLC)i))
+            {
+                Installer::DLCSource dlcSource;
+                fillDLCSource((DLC)i, dlcSource);
+
+                if (!checkFiles(dlcSource.filePairs, dlcSource.fileHashes, baseDirectory / dlcSource.targetSubDirectory, journal, progressCallback, checkSizeOnly))
+                {
+                    return false;
+                }
+            }
+        }
+    }
+
+    return true;
+}
+
 bool Installer::computeTotalSize(std::span<const FilePair> filePairs, const uint64_t *fileHashes, VirtualFileSystem &sourceVfs, Journal &journal, uint64_t &totalSize)
 {
     for (FilePair pair : filePairs)
@@ -272,6 +412,27 @@ bool Installer::computeTotalSize(std::span<const FilePair> filePairs, const uint
     return true;
 }
 
+bool Installer::checkFiles(std::span<const FilePair> filePairs, const uint64_t *fileHashes, const std::filesystem::path &targetDirectory, Journal &journal, const std::function<bool()> &progressCallback, bool checkSizeOnly)
+{
+    FilePair validationPair = {};
+    uint32_t validationHashIndex = 0;
+    uint32_t hashIndex = 0;
+    uint32_t hashCount = 0;
+    std::vector<uint8_t> fileData;
+    for (FilePair pair : filePairs)
+    {
+        hashIndex = hashCount;
+        hashCount += pair.second;
+
+        if (!checkFile(pair, &fileHashes[hashIndex], targetDirectory, fileData, journal, progressCallback, checkSizeOnly))
+        {
+            return false;
+        }
+    }
+
+    return true;
+}
+
 bool Installer::copyFiles(std::span<const FilePair> filePairs, const uint64_t *fileHashes, VirtualFileSystem &sourceVfs, const std::filesystem::path &targetDirectory, const std::string &validationFile, bool skipHashChecks, Journal &journal, const std::function<bool()> &progressCallback)
 {
     std::error_code ec;
@@ -387,39 +548,8 @@ bool Installer::parseSources(const Input &input, Journal &journal, Sources &sour
         }
 
         DLC dlc = detectDLC(path, *dlcSource.sourceVfs, journal);
-        switch (dlc)
+        if (!fillDLCSource(dlc, dlcSource))
         {
-        case DLC::Spagonia:
-            dlcSource.filePairs = { SpagoniaFiles, SpagoniaFilesSize };
-            dlcSource.fileHashes = SpagoniaHashes;
-            dlcSource.targetSubDirectory = SpagoniaDirectory;
-            break;
-        case DLC::Chunnan:
-            dlcSource.filePairs = { ChunnanFiles, ChunnanFilesSize };
-            dlcSource.fileHashes = ChunnanHashes;
-            dlcSource.targetSubDirectory = ChunnanDirectory;
-            break;
-        case DLC::Mazuri:
-            dlcSource.filePairs = { MazuriFiles, MazuriFilesSize };
-            dlcSource.fileHashes = MazuriHashes;
-            dlcSource.targetSubDirectory = MazuriDirectory;
-            break;
-        case DLC::Holoska:
-            dlcSource.filePairs = { HoloskaFiles, HoloskaFilesSize };
-            dlcSource.fileHashes = HoloskaHashes;
-            dlcSource.targetSubDirectory = HoloskaDirectory;
-            break;
-        case DLC::ApotosShamar:
-            dlcSource.filePairs = { ApotosShamarFiles, ApotosShamarFilesSize };
-            dlcSource.fileHashes = ApotosShamarHashes;
-            dlcSource.targetSubDirectory = ApotosShamarDirectory;
-            break;
-        case DLC::EmpireCityAdabat:
-            dlcSource.filePairs = { EmpireCityAdabatFiles, EmpireCityAdabatFilesSize };
-            dlcSource.fileHashes = EmpireCityAdabatHashes;
-            dlcSource.targetSubDirectory = EmpireCityAdabatDirectory;
-            break;
-        default:
             return false;
         }
 
diff --git a/UnleashedRecomp/install/installer.h b/UnleashedRecomp/install/installer.h
index 9f216a26..8bc04777 100644
--- a/UnleashedRecomp/install/installer.h
+++ b/UnleashedRecomp/install/installer.h
@@ -75,7 +75,9 @@ struct Installer
     static bool checkGameInstall(const std::filesystem::path &baseDirectory, std::filesystem::path &modulePath);
     static bool checkDLCInstall(const std::filesystem::path &baseDirectory, DLC dlc);
     static bool checkAllDLC(const std::filesystem::path &baseDirectory);
+    static bool checkInstallIntegrity(const std::filesystem::path &baseDirectory, Journal &journal, const std::function<bool()> &progressCallback);
     static bool computeTotalSize(std::span<const FilePair> filePairs, const uint64_t *fileHashes, VirtualFileSystem &sourceVfs, Journal &journal, uint64_t &totalSize);
+    static bool checkFiles(std::span<const FilePair> filePairs, const uint64_t *fileHashes, const std::filesystem::path &targetDirectory, Journal &journal, const std::function<bool()> &progressCallback, bool checkSizeOnly);
     static bool copyFiles(std::span<const FilePair> filePairs, const uint64_t *fileHashes, VirtualFileSystem &sourceVfs, const std::filesystem::path &targetDirectory, const std::string &validationFile, bool skipHashChecks, Journal &journal, const std::function<bool()> &progressCallback);
     static bool parseContent(const std::filesystem::path &sourcePath, std::unique_ptr<VirtualFileSystem> &targetVfs, Journal &journal);
     static bool parseSources(const Input &input, Journal &journal, Sources &sources);
diff --git a/UnleashedRecomp/locale/locale.cpp b/UnleashedRecomp/locale/locale.cpp
index 5eb3d401..8d1e74d1 100644
--- a/UnleashedRecomp/locale/locale.cpp
+++ b/UnleashedRecomp/locale/locale.cpp
@@ -703,6 +703,28 @@ std::unordered_map<std::string_view, std::unordered_map<ELanguage, std::string>>
             { ELanguage::Italian,  "Impossibile trovare il modulo \"%s\".\n\nAssicurati che:\n\n- Hai estratto questa copia di Unleashed Recompiled correttamente e non solo il file *.exe.\n- Non stai eseguendo Unleashed Recompiled da un file *.zip." }
         }
     },
+    {
+        "IntegrityCheck_Success",
+        {
+            { ELanguage::English,  "Installation check has finished.\n\nAll files seem to be correct.\n\nThe game will now close. Remove the launch argument to play the game." },
+            { ELanguage::Japanese, "インストールチェックが終了しました\n\nすべてのファイルは正しいようです\n\nゲームは終了します、ゲームをプレイするには起動引数を削除してください" },
+            { ELanguage::German,  "Die Installation wurde überprüft.\n\nAlle Dateien scheinen korrekt zu sein.\n\nDas Spiel wird nun geschlossen. Entferne die Startoption, um das Spiel zu spielen." },
+            { ELanguage::French,  "La vérification de l'installation est terminée.\n\nTous les fichiers semblent corrects.\n\nL'application va maintenant se fermer. Retirez l'argument de lancement pour pouvoir lancer le jeu." },
+            { ELanguage::Spanish,  "La verificación de la instalación ha terminado.\n\nTodos los archivos parecen correctos.\n\nEl juego se cerrará ahora. Elimina el argumento de lanzamiento para jugar al juego." },
+            { ELanguage::Italian,  "La verifica dei file d'installazione è terminata.\n\nTutti i file sembrano corretti.\n\nIl gioco si chiuderà. Rimuovi l'argomento di avvio per poter giocare." }
+        }
+    },
+    {
+        "IntegrityCheck_Failed",
+        {
+            { ELanguage::English,  "Installation check has failed.\n\nError: %s\n\nThe game will now close. Try reinstalling the game by using the --install launch argument." },
+            { ELanguage::Japanese, "インストールチェックに失敗しました\n\nエラー：%s\n\nゲームは終了します、--install 起動引数を使用してゲームを再インストールしてください" },
+            { ELanguage::German,  "Die Installationsprüfung ist fehlgeschlagen.\n\nFehler: %s\n\nDas Spiel wird nun geschlossen. Versuche das Spiel durch Verwendung der Startoption --install neu zu installieren." },
+            { ELanguage::French,  "La vérification de l'installation a échoué.\n\nErreur : %s\n\nL'application va maintenant se fermer. Essayez de réinstaller le jeu en utilisant l'argument de lancement --install." },
+            { ELanguage::Spanish,  "La verificación de la instalación ha fallado.\n\nError: %s\n\nEl juego se cerrará ahora. Intenta reinstalar el juego utilizando el argumento de lanzamiento --install." },
+            { ELanguage::Italian,  "La verifica dei file d'installazione non è andata a buon fine.\n\nErrore: %s\n\nIl gioco si chiuderà. Prova a reinstallare il gioco utilizzando l'argomento di avvio --install." }
+        }
+    },
     {
         "Common_On",
         {
diff --git a/UnleashedRecomp/main.cpp b/UnleashedRecomp/main.cpp
index 5ef5cd46..526a3713 100644
--- a/UnleashedRecomp/main.cpp
+++ b/UnleashedRecomp/main.cpp
@@ -13,6 +13,7 @@
 #include <hid/hid.h>
 #include <user/config.h>
 #include <user/paths.h>
+#include <user/persistent_storage_manager.h>
 #include <user/registry.h>
 #include <kernel/xdbf.h>
 #include <install/installer.h>
@@ -200,6 +201,7 @@ int main(int argc, char *argv[])
     bool forceInstaller = false;
     bool forceDLCInstaller = false;
     bool useDefaultWorkingDirectory = false;
+    bool forceInstallationCheck = false;
     bool graphicsApiRetry = false;
     const char *sdlVideoDriver = nullptr;
 
@@ -208,6 +210,7 @@ int main(int argc, char *argv[])
         forceInstaller = forceInstaller || (strcmp(argv[i], "--install") == 0);
         forceDLCInstaller = forceDLCInstaller || (strcmp(argv[i], "--install-dlc") == 0);
         useDefaultWorkingDirectory = useDefaultWorkingDirectory || (strcmp(argv[i], "--use-cwd") == 0);
+        forceInstallationCheck = forceInstallationCheck || (strcmp(argv[i], "--install-check") == 0);
         graphicsApiRetry = graphicsApiRetry || (strcmp(argv[i], "--graphics-api-retry") == 0);
 
         if (strcmp(argv[i], "--sdl-video-driver") == 0)
@@ -227,6 +230,62 @@ int main(int argc, char *argv[])
     }
 
     Config::Load();
+    
+    if (!PersistentStorageManager::LoadBinary())
+        LOGFN_ERROR("Failed to load persistent storage binary... (status code {})", (int)PersistentStorageManager::BinStatus);
+
+    if (forceInstallationCheck)
+    {
+        // Create the console to show progress to the user, otherwise it will seem as if the game didn't boot at all.
+        os::process::ShowConsole();
+
+        Journal journal;
+        double lastProgressMiB = 0.0;
+        double lastTotalMib = 0.0;
+        Installer::checkInstallIntegrity(GAME_INSTALL_DIRECTORY, journal, [&]()
+        {
+            constexpr double MiBDivisor = 1024.0 * 1024.0;
+            constexpr double MiBProgressThreshold = 128.0;
+            double progressMiB = double(journal.progressCounter) / MiBDivisor;
+            double totalMiB = double(journal.progressTotal) / MiBDivisor;
+            if (journal.progressCounter > 0)
+            {
+                if ((progressMiB - lastProgressMiB) > MiBProgressThreshold)
+                {
+                    fprintf(stdout, "Checking files: %0.2f MiB / %0.2f MiB\n", progressMiB, totalMiB);
+                    lastProgressMiB = progressMiB;
+                }
+            }
+            else
+            {
+                if ((totalMiB - lastTotalMib) > MiBProgressThreshold)
+                {
+                    fprintf(stdout, "Scanning files: %0.2f MiB\n", totalMiB);
+                    lastTotalMib = totalMiB;
+                }
+            }
+
+            return true;
+        });
+
+        char resultText[512];
+        uint32_t messageBoxStyle;
+        if (journal.lastResult == Journal::Result::Success)
+        {
+            snprintf(resultText, sizeof(resultText), "%s", Localise("IntegrityCheck_Success").c_str());
+            fprintf(stdout, "%s\n", resultText);
+            messageBoxStyle = SDL_MESSAGEBOX_INFORMATION;
+        }
+        else
+        {
+            snprintf(resultText, sizeof(resultText), Localise("IntegrityCheck_Failed").c_str(), journal.lastErrorMessage.c_str());
+            fprintf(stderr, "%s\n", resultText);
+            messageBoxStyle = SDL_MESSAGEBOX_ERROR;
+        }
+
+        SDL_ShowSimpleMessageBox(messageBoxStyle, GameWindow::GetTitle(), resultText, GameWindow::s_pWindow);
+        std::_Exit(int(journal.lastResult));
+    }
 
 #if defined(_WIN32) && defined(UNLEASHED_RECOMP_D3D12)
     for (auto& dll : g_D3D12RequiredModules)
diff --git a/UnleashedRecomp/patches/CTitleStateIntro_patches.cpp b/UnleashedRecomp/patches/CTitleStateIntro_patches.cpp
index d4a05fc5..4affb80a 100644
--- a/UnleashedRecomp/patches/CTitleStateIntro_patches.cpp
+++ b/UnleashedRecomp/patches/CTitleStateIntro_patches.cpp
@@ -2,6 +2,7 @@
 #include <api/SWA.h>
 #include <install/update_checker.h>
 #include <locale/locale.h>
+#include <os/logger.h>
 #include <ui/fader.h>
 #include <ui/message_window.h>
 #include <user/achievement_manager.h>
@@ -64,16 +65,16 @@ static bool ProcessCorruptAchievementsMessage()
     if (!g_corruptAchievementsMessageOpen)
         return false;
 
-    auto message = AchievementManager::Status == EAchStatus::IOError
+    auto message = AchievementManager::BinStatus == EAchBinStatus::IOError
         ? Localise("Title_Message_AchievementDataIOError")
         : Localise("Title_Message_AchievementDataCorrupt");
 
     if (MessageWindow::Open(message, &g_corruptAchievementsMessageResult) == MSG_CLOSED)
     {
-        // Allow user to proceed if the achievement data couldn't be loaded.
-        // Restarting may fix this error, so it isn't worth clearing the data for.
-        if (AchievementManager::Status != EAchStatus::IOError)
-            AchievementManager::Save(true);
+        // Create a new save file if the file was successfully loaded and failed validation.
+        // If the file couldn't be opened, restarting may fix this error, so it isn't worth clearing the data for.
+        if (AchievementManager::BinStatus != EAchBinStatus::IOError)
+            AchievementManager::SaveBinary(true);
 
         g_corruptAchievementsMessageOpen = false;
         g_corruptAchievementsMessageOpen.notify_one();
@@ -135,9 +136,10 @@ void PressStartSaveLoadThreadMidAsmHook()
         g_faderBegun.wait(true);
     }
 
-    AchievementManager::Load();
+    if (!AchievementManager::LoadBinary())
+        LOGFN_ERROR("Failed to load achievement data... (status code {})", (int)AchievementManager::BinStatus);
 
-    if (AchievementManager::Status != EAchStatus::Success)
+    if (AchievementManager::BinStatus != EAchBinStatus::Success)
     {
         g_corruptAchievementsMessageOpen = true;
         g_corruptAchievementsMessageOpen.wait(true);
diff --git a/UnleashedRecomp/patches/misc_patches.cpp b/UnleashedRecomp/patches/misc_patches.cpp
index ed225827..ec4e1a8b 100644
--- a/UnleashedRecomp/patches/misc_patches.cpp
+++ b/UnleashedRecomp/patches/misc_patches.cpp
@@ -1,6 +1,7 @@
 #include <api/SWA.h>
 #include <ui/game_window.h>
 #include <user/achievement_manager.h>
+#include <user/persistent_storage_manager.h>
 #include <user/config.h>
 
 void AchievementManagerUnlockMidAsmHook(PPCRegister& id)
@@ -172,3 +173,23 @@ PPC_FUNC(sub_82B4DB48)
 
     __imp__sub_82B4DB48(ctx, base);
 }
+
+// DLC save data flag check.
+// 
+// The DLC checks are fundamentally broken in this game, resulting in this method always
+// returning true and displaying the DLC info message when it shouldn't be.
+// 
+// The original intent here seems to have been to display the message every time new DLC
+// content is installed, but the flags in the save data never get written to properly,
+// causing this function to always pass in some way.
+//
+// We bypass the save data completely and write to external persistent storage to store
+// whether we've seen the DLC info message instead. This way we can retain the original
+// broken game behaviour, whilst also providing a fix for this issue that is safe.
+PPC_FUNC_IMPL(__imp__sub_824EE620);
+PPC_FUNC(sub_824EE620)
+{
+    __imp__sub_824EE620(ctx, base);
+
+    ctx.r3.u32 = PersistentStorageManager::ShouldDisplayDLCMessage(true);
+}
diff --git a/UnleashedRecomp/patches/resident_patches.cpp b/UnleashedRecomp/patches/resident_patches.cpp
index 64a220d7..2741d0e9 100644
--- a/UnleashedRecomp/patches/resident_patches.cpp
+++ b/UnleashedRecomp/patches/resident_patches.cpp
@@ -2,11 +2,10 @@
 #include <hid/hid.h>
 #include <os/logger.h>
 #include <user/achievement_manager.h>
+#include <user/persistent_storage_manager.h>
 #include <user/config.h>
 #include <app.h>
 
-bool m_isSavedAchievementData = false;
-
 // SWA::Message::MsgRequestStartLoading::Impl
 PPC_FUNC_IMPL(__imp__sub_824DCF38);
 PPC_FUNC(sub_824DCF38)
@@ -99,20 +98,23 @@ PPC_FUNC(sub_824E5170)
 
     App::s_isSaving = pSaveIcon->m_IsVisible;
 
+    static bool isSavedExtraData = false;
+
     if (pSaveIcon->m_IsVisible)
     {
         App::s_isSaveDataCorrupt = false;
 
-        if (!m_isSavedAchievementData)
+        if (!isSavedExtraData)
         {
-            AchievementManager::Save();
+            AchievementManager::SaveBinary();
+            PersistentStorageManager::SaveBinary();
 
-            m_isSavedAchievementData = true;
+            isSavedExtraData = true;
         }
     }
     else
     {
-        m_isSavedAchievementData = false;
+        isSavedExtraData = false;
     }
 }
 
diff --git a/UnleashedRecomp/user/achievement_data.cpp b/UnleashedRecomp/user/achievement_data.cpp
index 2369b0df..dd734659 100644
--- a/UnleashedRecomp/user/achievement_data.cpp
+++ b/UnleashedRecomp/user/achievement_data.cpp
@@ -11,7 +11,7 @@ bool AchievementData::VerifySignature() const
 
 bool AchievementData::VerifyVersion() const
 {
-    return Version == AchVersion ACH_VERSION;
+    return Version <= ACH_VERSION;
 }
 
 bool AchievementData::VerifyChecksum()
diff --git a/UnleashedRecomp/user/achievement_data.h b/UnleashedRecomp/user/achievement_data.h
index bd38d219..3c8c1a5a 100644
--- a/UnleashedRecomp/user/achievement_data.h
+++ b/UnleashedRecomp/user/achievement_data.h
@@ -4,27 +4,12 @@
 
 #define ACH_FILENAME  "ACH-DATA"
 #define ACH_SIGNATURE { 'A', 'C', 'H', ' ' }
-#define ACH_VERSION   { 1, 0, 0 }
+#define ACH_VERSION   1
 #define ACH_RECORDS   50
 
 class AchievementData
 {
 public:
-    struct AchVersion
-    {
-        uint8_t Major;
-        uint8_t Minor;
-        uint8_t Revision;
-        uint8_t Reserved;
-
-        bool operator==(const AchVersion& other) const
-        {
-            return Major == other.Major &&
-                   Minor == other.Minor &&
-                   Revision == other.Revision;
-        }
-    };
-
 #pragma pack(push, 1)
     struct AchRecord
     {
@@ -35,10 +20,10 @@ public:
 #pragma pack(pop)
 
     char Signature[4] ACH_SIGNATURE;
-    AchVersion Version ACH_VERSION;
-    uint32_t Checksum;
-    uint32_t Reserved;
-    AchRecord Records[ACH_RECORDS];
+    uint32_t Version{ ACH_VERSION };
+    uint32_t Checksum{};
+    uint32_t Reserved{};
+    AchRecord Records[ACH_RECORDS]{};
 
     bool VerifySignature() const;
     bool VerifyVersion() const;
diff --git a/UnleashedRecomp/user/achievement_manager.cpp b/UnleashedRecomp/user/achievement_manager.cpp
index dbc6c242..6d2a5772 100644
--- a/UnleashedRecomp/user/achievement_manager.cpp
+++ b/UnleashedRecomp/user/achievement_manager.cpp
@@ -105,11 +105,11 @@ void AchievementManager::Reset()
     *(bool*)g_memory.Translate(0x833647C4) = false;
 }
 
-void AchievementManager::Load()
+bool AchievementManager::LoadBinary()
 {
     AchievementManager::Reset();
 
-    Status = EAchStatus::Success;
+    BinStatus = EAchBinStatus::Success;
 
     auto dataPath = GetDataPath(true);
 
@@ -119,7 +119,7 @@ void AchievementManager::Load()
         dataPath = GetDataPath(false);
 
         if (!std::filesystem::exists(dataPath))
-            return;
+            return true;
     }
 
     std::error_code ec;
@@ -128,16 +128,16 @@ void AchievementManager::Load()
 
     if (fileSize != dataSize)
     {
-        Status = EAchStatus::BadFileSize;
-        return;
+        BinStatus = EAchBinStatus::BadFileSize;
+        return false;
     }
 
     std::ifstream file(dataPath, std::ios::binary);
 
     if (!file)
     {
-        Status = EAchStatus::IOError;
-        return;
+        BinStatus = EAchBinStatus::IOError;
+        return false;
     }
 
     AchievementData data{};
@@ -146,19 +146,18 @@ void AchievementManager::Load()
 
     if (!data.VerifySignature())
     {
-        Status = EAchStatus::BadSignature;
+        BinStatus = EAchBinStatus::BadSignature;
         file.close();
-        return;
+        return false;
     }
 
     file.read((char*)&data.Version, sizeof(data.Version));
 
-    // TODO: upgrade in future if the version changes.
     if (!data.VerifyVersion())
     {
-        Status = EAchStatus::BadVersion;
+        BinStatus = EAchBinStatus::BadVersion;
         file.close();
-        return;
+        return false;
     }
 
     file.seekg(0);
@@ -166,22 +165,24 @@ void AchievementManager::Load()
 
     if (!data.VerifyChecksum())
     {
-        Status = EAchStatus::BadChecksum;
+        BinStatus = EAchBinStatus::BadChecksum;
         file.close();
-        return;
+        return false;
     }
 
     file.close();
 
     memcpy(&Data, &data, dataSize);
+
+    return true;
 }
 
-void AchievementManager::Save(bool ignoreStatus)
+bool AchievementManager::SaveBinary(bool ignoreStatus)
 {
-    if (!ignoreStatus && Status != EAchStatus::Success)
+    if (!ignoreStatus && BinStatus != EAchBinStatus::Success)
     {
         LOGN_WARNING("Achievement data will not be saved in this session!");
-        return;
+        return false;
     }
 
     LOGN("Saving achievements...");
@@ -191,7 +192,7 @@ void AchievementManager::Save(bool ignoreStatus)
     if (!file)
     {
         LOGN_ERROR("Failed to write achievement data.");
-        return;
+        return false;
     }
 
     Data.Checksum = Data.CalculateChecksum();
@@ -199,5 +200,7 @@ void AchievementManager::Save(bool ignoreStatus)
     file.write((const char*)&Data, sizeof(AchievementData));
     file.close();
 
-    Status = EAchStatus::Success;
+    BinStatus = EAchBinStatus::Success;
+
+    return true;
 }
diff --git a/UnleashedRecomp/user/achievement_manager.h b/UnleashedRecomp/user/achievement_manager.h
index eab9c829..4bff7577 100644
--- a/UnleashedRecomp/user/achievement_manager.h
+++ b/UnleashedRecomp/user/achievement_manager.h
@@ -2,7 +2,7 @@
 
 #include <user/achievement_data.h>
 
-enum class EAchStatus
+enum class EAchBinStatus
 {
     Success,
     IOError,
@@ -16,7 +16,7 @@ class AchievementManager
 {
 public:
     static inline AchievementData Data{};
-    static inline EAchStatus Status{};
+    static inline EAchBinStatus BinStatus{ EAchBinStatus::Success };
 
     static std::filesystem::path GetDataPath(bool checkForMods)
     {
@@ -29,6 +29,6 @@ public:
     static void Unlock(uint16_t id);
     static void UnlockAll();
     static void Reset();
-    static void Load();
-    static void Save(bool ignoreStatus = false);
+    static bool LoadBinary();
+    static bool SaveBinary(bool ignoreStatus = false);
 };
diff --git a/UnleashedRecomp/user/persistent_data.cpp b/UnleashedRecomp/user/persistent_data.cpp
new file mode 100644
index 00000000..f087f39e
--- /dev/null
+++ b/UnleashedRecomp/user/persistent_data.cpp
@@ -0,0 +1,13 @@
+#include "persistent_data.h"
+
+bool PersistentData::VerifySignature() const
+{
+    char sig[4] = EXT_SIGNATURE;
+
+    return memcmp(Signature, sig, sizeof(Signature)) == 0;
+}
+
+bool PersistentData::VerifyVersion() const
+{
+    return Version <= EXT_VERSION;
+}
diff --git a/UnleashedRecomp/user/persistent_data.h b/UnleashedRecomp/user/persistent_data.h
new file mode 100644
index 00000000..fec827fa
--- /dev/null
+++ b/UnleashedRecomp/user/persistent_data.h
@@ -0,0 +1,30 @@
+#pragma once
+
+#include <user/paths.h>
+
+#define EXT_FILENAME    "EXT-DATA"
+#define EXT_SIGNATURE   { 'E', 'X', 'T', ' ' }
+#define EXT_VERSION     1
+
+enum class EDLCFlag
+{
+    ApotosAndShamar,
+    Spagonia,
+    Chunnan,
+    Mazuri,
+    Holoska,
+    EmpireCityAndAdabat,
+    Count
+};
+
+class PersistentData
+{
+public:
+    char Signature[4] EXT_SIGNATURE;
+    uint32_t Version{ EXT_VERSION };
+    uint64_t Reserved{};
+    bool DLCFlags[6]{};
+
+    bool VerifySignature() const;
+    bool VerifyVersion() const;
+};
diff --git a/UnleashedRecomp/user/persistent_storage_manager.cpp b/UnleashedRecomp/user/persistent_storage_manager.cpp
new file mode 100644
index 00000000..6b92d239
--- /dev/null
+++ b/UnleashedRecomp/user/persistent_storage_manager.cpp
@@ -0,0 +1,117 @@
+#include "persistent_storage_manager.h"
+#include <install/installer.h>
+#include <os/logger.h>
+#include <user/paths.h>
+
+bool PersistentStorageManager::ShouldDisplayDLCMessage(bool setOffendingDLCFlag)
+{
+    if (BinStatus != EExtBinStatus::Success)
+        return true;
+
+    static std::unordered_map<EDLCFlag, DLC> flags =
+    {
+        { EDLCFlag::ApotosAndShamar, DLC::ApotosShamar },
+        { EDLCFlag::Spagonia, DLC::Spagonia },
+        { EDLCFlag::Chunnan, DLC::Chunnan },
+        { EDLCFlag::Mazuri, DLC::Mazuri },
+        { EDLCFlag::Holoska, DLC::Holoska },
+        { EDLCFlag::EmpireCityAndAdabat, DLC::EmpireCityAdabat }
+    };
+
+    auto result = false;
+
+    for (auto& pair : flags)
+    {
+        if (!Data.DLCFlags[(int)pair.first] && Installer::checkDLCInstall(GetGamePath(), pair.second))
+        {
+            if (setOffendingDLCFlag)
+                Data.DLCFlags[(int)pair.first] = true;
+
+            result = true;
+        }
+    }
+
+    return result;
+}
+
+bool PersistentStorageManager::LoadBinary()
+{
+    BinStatus = EExtBinStatus::Success;
+
+    auto dataPath = GetDataPath(true);
+
+    if (!std::filesystem::exists(dataPath))
+    {
+        // Try loading base persistent data as fallback.
+        dataPath = GetDataPath(false);
+
+        if (!std::filesystem::exists(dataPath))
+            return true;
+    }
+
+    std::error_code ec;
+    auto fileSize = std::filesystem::file_size(dataPath, ec);
+    auto dataSize = sizeof(PersistentData);
+
+    if (fileSize != dataSize)
+    {
+        BinStatus = EExtBinStatus::BadFileSize;
+        return false;
+    }
+
+    std::ifstream file(dataPath, std::ios::binary);
+
+    if (!file)
+    {
+        BinStatus = EExtBinStatus::IOError;
+        return false;
+    }
+
+    PersistentData data{};
+
+    file.read((char*)&data.Signature, sizeof(data.Signature));
+
+    if (!data.VerifySignature())
+    {
+        BinStatus = EExtBinStatus::BadSignature;
+        file.close();
+        return false;
+    }
+
+    file.read((char*)&data.Version, sizeof(data.Version));
+
+    if (!data.VerifyVersion())
+    {
+        BinStatus = EExtBinStatus::BadVersion;
+        file.close();
+        return false;
+    }
+
+    file.seekg(0);
+    file.read((char*)&data, sizeof(data));
+    file.close();
+
+    memcpy(&Data, &data, dataSize);
+
+    return true;
+}
+
+bool PersistentStorageManager::SaveBinary()
+{
+    LOGN("Saving persistent storage binary...");
+
+    std::ofstream file(GetDataPath(true), std::ios::binary);
+
+    if (!file)
+    {
+        LOGN_ERROR("Failed to write persistent storage binary.");
+        return false;
+    }
+
+    file.write((const char*)&Data, sizeof(PersistentData));
+    file.close();
+
+    BinStatus = EExtBinStatus::Success;
+
+    return true;
+}
diff --git a/UnleashedRecomp/user/persistent_storage_manager.h b/UnleashedRecomp/user/persistent_storage_manager.h
new file mode 100644
index 00000000..4cad7b88
--- /dev/null
+++ b/UnleashedRecomp/user/persistent_storage_manager.h
@@ -0,0 +1,28 @@
+#pragma once
+
+#include <user/persistent_data.h>
+
+enum class EExtBinStatus
+{
+    Success,
+    IOError,
+    BadFileSize,
+    BadSignature,
+    BadVersion
+};
+
+class PersistentStorageManager
+{
+public:
+    static inline PersistentData Data{};
+    static inline EExtBinStatus BinStatus{ EExtBinStatus::Success };
+
+    static std::filesystem::path GetDataPath(bool checkForMods)
+    {
+        return GetSavePath(checkForMods) / EXT_FILENAME;
+    }
+
+    static bool ShouldDisplayDLCMessage(bool setOffendingDLCFlag);
+    static bool LoadBinary();
+    static bool SaveBinary();
+};