Add HYTALE_NOOP_TEST to test read/write without patching

Tests if our file read/write process itself causes corruption.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

PKGBUILD

@@ -14,15 +14,15 @@ source=("$url/archive/v$pkgver.tar.gz" "Hytale-F2P.desktop")
 sha256sums=('SKIP' '46488fada4775d9976d7b7b62f8d1f1f8d9a9a9d8f8aa9af4f2e2153019f6a30')
 
 build() {
-   cd "$_pkgname-$pkgver"
+   cd "$pkgname-$pkgver"
    npm ci
    npm run build:arch
 }
 
 package() {
-  cd "$_pkgname-$pkgver"
-  install -d "$pkgdir/opt/$_pkgname"
-  cp -r dist/linux-unpacked/* "$pkgdir/opt/$_pkgname"
-  install -Dm644 "$srcdir/$_pkgname.desktop" "$pkgdir/usr/share/applications/$_pkgname.desktop"
-  install -Dm644 GUI/icon.png "$pkgdir/usr/share/icons/hicolor/256x256/apps/$_pkgname.png"
+  cd "$pkgname-$pkgver"
+  install -d "$pkgdir/opt/$pkgname"
+  cp -r dist/linux-unpacked/* "$pkgdir/opt/$pkgname"
+  install -Dm644 "$srcdir/$pkgname.desktop" "$pkgdir/usr/share/applications/$pkgname.desktop"
+  install -Dm644 GUI/icon.png "$pkgdir/usr/share/icons/hicolor/256x256/apps/$pkgname.png"
 }

backend/core/paths.js

@@ -14,6 +14,21 @@ function getAppDir() {
   }
 }
 
+/**
+ * Get centralized UserData saves directory (NEW in 2.1.2)
+ * UserData is now stored separately from game installation
+ */
+function getHytaleSavesDir() {
+  const home = os.homedir();
+  if (process.platform === 'win32') {
+    return path.join(home, 'AppData', 'Local', 'HytaleSaves');
+  } else if (process.platform === 'darwin') {
+    return path.join(home, 'Library', 'Application Support', 'HytaleSaves');
+  } else {
+    return path.join(home, '.hytalesaves');
+  }
+}
+
 const DEFAULT_APP_DIR = getAppDir();
 
 function getResolvedAppDir(customPath) {
@@ -218,20 +233,8 @@ async function getModsPath(customInstallPath = null) {
 
 function getProfilesDir(customInstallPath = null) {
   try {
-    // get UserData path
-    let installPath = customInstallPath;
-    if (!installPath) {
-        const configFile = path.join(DEFAULT_APP_DIR, 'config.json');
-        if (fs.existsSync(configFile)) {
-            const config = JSON.parse(fs.readFileSync(configFile, 'utf8'));
-            installPath = config.installPath || '';
-        }
-    }
-    if (!installPath) installPath = getAppDir();
-    
-    const branch = loadVersionBranch();
-    const gameLatest = path.join(installPath, branch, 'package', 'game', 'latest');
-    const userDataPath = findUserDataPath(gameLatest);
+    // NEW 2.1.2: Use centralized UserData location
+    const userDataPath = getHytaleSavesDir();
     const profilesDir = path.join(userDataPath, 'Profiles');
     
     if (!fs.existsSync(profilesDir)) {
@@ -247,6 +250,7 @@ function getProfilesDir(customInstallPath = null) {
 
 module.exports = {
   getAppDir,
+  getHytaleSavesDir,
   getResolvedAppDir,
   expandHome,
   APP_DIR,

backend/managers/gameLauncher.js

@@ -12,6 +12,7 @@ const { resolveJavaPath, getJavaExec, getBundledJavaPath, detectSystemJava, JAVA
 const { getLatestClientVersion } = require('../services/versionManager');
 const { updateGameFiles } = require('./gameManager');
 const { syncModsForCurrentProfile } = require('./modManager');
+const { getUserDataPath } = require('../utils/userDataMigration');
 
 // Client patcher for custom auth server (sanasol.ws)
 let clientPatcher = null;
@@ -106,7 +107,9 @@ async function launchGame(playerName = 'Player', progressCallback, javaPathOverr
   const customAppDir = getResolvedAppDir(installPathOverride);
   const customGameDir = path.join(customAppDir, branch, 'package', 'game', 'latest');
   const customJreDir = path.join(customAppDir, branch, 'package', 'jre', 'latest');
-  const userDataDir = path.join(customGameDir, 'Client', 'UserData');
+  
+  // NEW 2.1.2: Use centralized UserData location
+  const userDataDir = getUserDataPath();
 
   const gameLatest = customGameDir;
   let clientPath = findClientPath(gameLatest);
@@ -282,6 +285,32 @@ exec "$REAL_JAVA" "\${ARGS[@]}"
    const gpuEnv = setupGpuEnvironment(gpuPreference);
    Object.assign(env, gpuEnv);
 
+   // Linux memory allocator fixes for "free(): invalid pointer" crashes
+   // on Steam Deck (glibc 2.41) and Ubuntu LTS
+   if (process.platform === 'linux') {
+     // Option 1: Disable glibc heap validation
+     env.MALLOC_CHECK_ = '0';
+
+     // Option 2: Try to use jemalloc if available (more robust allocator)
+     // User can set HYTALE_USE_JEMALLOC=1 to enable
+     if (process.env.HYTALE_USE_JEMALLOC === '1') {
+       const jemalloc = require('fs').existsSync('/usr/lib/libjemalloc.so.2')
+         ? '/usr/lib/libjemalloc.so.2'
+         : require('fs').existsSync('/usr/lib/x86_64-linux-gnu/libjemalloc.so.2')
+           ? '/usr/lib/x86_64-linux-gnu/libjemalloc.so.2'
+           : null;
+
+       if (jemalloc) {
+         env.LD_PRELOAD = jemalloc + (env.LD_PRELOAD ? ':' + env.LD_PRELOAD : '');
+         console.log(`Linux: Using jemalloc allocator (${jemalloc})`);
+       } else {
+         console.log('Linux: jemalloc not found, using glibc with MALLOC_CHECK_=0');
+       }
+     } else {
+       console.log('Linux: Using glibc with MALLOC_CHECK_=0 (set HYTALE_USE_JEMALLOC=1 to try jemalloc)');
+     }
+   }
+
   try {
     let spawnOptions = {
       stdio: ['ignore', 'pipe', 'pipe'],

backend/managers/gameManager.js

@@ -9,7 +9,7 @@ const { installButler } = require('./butlerManager');
 const { downloadAndReplaceHomePageUI, downloadAndReplaceLogo } = require('./uiFileManager');
 const { saveUsername, saveInstallPath, loadJavaPath, CONFIG_FILE, loadConfig, loadVersionBranch, saveVersionClient, loadVersionClient } = require('../core/config');
 const { resolveJavaPath, detectSystemJava, downloadJRE, getJavaExec, getBundledJavaPath } = require('./javaManager');
-const userDataBackup = require('../utils/userDataBackup');
+const { getUserDataPath, migrateUserDataToCentralized } = require('../utils/userDataMigration');
 
 async function downloadPWR(branch = 'release', fileName = '4.pwr', progressCallback, cacheDir = CACHE_DIR, manualRetry = false) {
   const osName = getOS();
@@ -308,31 +308,25 @@ async function applyPWR(pwrFile, progressCallback, gameDir = GAME_DIR, toolsDir
 
 async function updateGameFiles(newVersion, progressCallback, gameDir = GAME_DIR, toolsDir = TOOLS_DIR, cacheDir = CACHE_DIR, branchOverride = null) {
   let tempUpdateDir;
-  let backupPath = null;
   const branch = branchOverride || loadVersionBranch();
   const installPath = path.dirname(path.dirname(path.dirname(path.dirname(gameDir))));
   
-  // Vérifier si on a version_client et version_branch dans config.json
   const config = loadConfig();
-  const hasVersionConfig = !!(config.version_client && config.version_branch);
-  const oldBranch = config.version_branch || 'release'; // L'ancienne branche pour le backup
-  console.log(`[UpdateGameFiles] hasVersionConfig: ${hasVersionConfig}`);
+  const oldBranch = config.version_branch || 'release';
   console.log(`[UpdateGameFiles] Switching from ${oldBranch} to ${branch}`);
   
   try {
-    if (progressCallback) {
-      progressCallback('Backing up user data...', 5, null, null, null);
-    }
-
-    // Backup UserData AVANT de télécharger/installer (critical for same-branch updates)
+    // NEW 2.1.2: Ensure UserData migration to centralized location
     try {
-      console.log(`[UpdateGameFiles] Attempting to backup UserData from old branch: ${oldBranch}`);
-      backupPath = await userDataBackup.backupUserData(installPath, oldBranch, hasVersionConfig);
-      if (backupPath) {
-        console.log(`[UpdateGameFiles] ✓ UserData backed up from ${oldBranch}: ${backupPath}`);
+      console.log('[UpdateGameFiles] Ensuring UserData migration...');
+      const migrationResult = await migrateUserDataToCentralized();
+      if (migrationResult.migrated) {
+        console.log('[UpdateGameFiles] ✓ UserData migrated to centralized location');
+      } else if (migrationResult.alreadyMigrated) {
+        console.log('[UpdateGameFiles] ✓ UserData already in centralized location');
       }
-    } catch (backupError) {
-      console.warn('[UpdateGameFiles] ✗ UserData backup failed:', backupError.message);
+    } catch (migrationError) {
+      console.warn('[UpdateGameFiles] UserData migration warning:', migrationError.message);
     }
 
     if (progressCallback) {
@@ -390,31 +384,9 @@ async function updateGameFiles(newVersion, progressCallback, gameDir = GAME_DIR,
     const logoResult = await downloadAndReplaceLogo(gameDir, progressCallback);
     console.log('Logo@2x.png update result after update:', logoResult);
 
-    // Ensure UserData directory exists
-    const userDataDir = path.join(gameDir, 'Client', 'UserData');
-    if (!fs.existsSync(userDataDir)) {
-      console.log(`[UpdateGameFiles] Creating UserData directory at: ${userDataDir}`);
-      fs.mkdirSync(userDataDir, { recursive: true });
-    }
-
-    if (progressCallback) {
-      progressCallback('Restoring user data...', 90, null, null, null);
-    }
-
-    // Restore UserData using new system
-    if (backupPath) {
-      try {
-        console.log(`[UpdateGameFiles] Restoring UserData from ${oldBranch} to ${branch}`);
-        console.log(`[UpdateGameFiles] Source backup: ${backupPath}`);
-        await userDataBackup.restoreUserData(backupPath, installPath, branch);
-        await userDataBackup.cleanupBackup(backupPath);
-        console.log(`[UpdateGameFiles] ✓ UserData migrated successfully from ${oldBranch} to ${branch}`);
-      } catch (restoreError) {
-        console.warn('[UpdateGameFiles] ✗ UserData restore failed:', restoreError.message);
-      }
-    } else {
-      console.log('[UpdateGameFiles] No backup to restore, empty UserData folder created');
-    }
+    // NEW 2.1.2: No longer create UserData in game installation
+    // UserData is now in centralized location (getUserDataPath())
+    console.log('[UpdateGameFiles] UserData is managed in centralized location');
 
     console.log(`Game files updated successfully to version: ${newVersion}`);
     
@@ -434,15 +406,6 @@ async function updateGameFiles(newVersion, progressCallback, gameDir = GAME_DIR,
   } catch (error) {
     console.error('Error updating game files:', error);
 
-    if (backupPath) {
-      try {
-        await userDataBackup.cleanupBackup(backupPath);
-        console.log('UserData backup cleaned up after error');
-      } catch (cleanupError) {
-        console.warn('Could not clean up UserData backup:', cleanupError.message);
-      }
-    }
-
     if (tempUpdateDir && fs.existsSync(tempUpdateDir)) {
       fs.rmSync(tempUpdateDir, { recursive: true, force: true });
     }
@@ -470,28 +433,18 @@ async function installGame(playerName = 'Player', progressCallback, javaPathOver
   const customToolsDir = path.join(customAppDir, 'butler');
   const customGameDir = path.join(customAppDir, branch, 'package', 'game', 'latest');
   const customJreDir = path.join(customAppDir, branch, 'package', 'jre', 'latest');
-  const userDataDir = path.join(customGameDir, 'Client', 'UserData');
-
-  // Vérifier si on a version_client et version_branch dans config.json
-  const config = loadConfig();
-  const hasVersionConfig = !!(config.version_client && config.version_branch);
-  console.log(`[InstallGame] Configuration detected - version_client: ${config.version_client}, version_branch: ${config.version_branch}`);
-  console.log(`[InstallGame] hasVersionConfig: ${hasVersionConfig}`);
-
-  // Backup UserData AVANT l'installation si nécessaire
-  let backupPath = null;
-  if (progressCallback) {
-    progressCallback('Checking for existing UserData...', 5, null, null, null);
-  }
 
+  // NEW 2.1.2: Ensure UserData migration to centralized location
   try {
-    console.log(`[InstallGame] Attempting UserData backup (hasVersionConfig: ${hasVersionConfig})...`);
-    backupPath = await userDataBackup.backupUserData(customAppDir, branch, hasVersionConfig);
-    if (backupPath) {
-      console.log(`[InstallGame] ✓ UserData backed up to: ${backupPath}`);
+    console.log('[InstallGame] Ensuring UserData migration...');
+    const migrationResult = await migrateUserDataToCentralized();
+    if (migrationResult.migrated) {
+      console.log('[InstallGame] ✓ UserData migrated to centralized location');
+    } else if (migrationResult.alreadyMigrated) {
+      console.log('[InstallGame] ✓ UserData already in centralized location');
     }
-  } catch (backupError) {
-    console.warn('[InstallGame] ✗ UserData backup failed:', backupError.message);
+  } catch (migrationError) {
+    console.warn('[InstallGame] UserData migration warning:', migrationError.message);
   }
 
   [customAppDir, customCacheDir, customToolsDir].forEach(dir => {
@@ -500,10 +453,6 @@ async function installGame(playerName = 'Player', progressCallback, javaPathOver
     }
   });
 
-  if (!fs.existsSync(userDataDir)) {
-    fs.mkdirSync(userDataDir, { recursive: true });
-  }
-
   saveUsername(playerName);
   if (installPathOverride) {
     saveInstallPath(installPathOverride);
@@ -595,29 +544,9 @@ async function installGame(playerName = 'Player', progressCallback, javaPathOver
   const logoResult = await downloadAndReplaceLogo(customGameDir, progressCallback);
   console.log('Logo@2x.png update result after installation:', logoResult);
 
-  // Ensure UserData directory exists
-  if (!fs.existsSync(userDataDir)) {
-    console.log(`[InstallGame] Creating UserData directory at: ${userDataDir}`);
-    fs.mkdirSync(userDataDir, { recursive: true });
-  }
-
-  // Restore UserData from backup if exists
-  if (backupPath) {
-    if (progressCallback) {
-      progressCallback('Restoring UserData...', 95, null, null, null);
-    }
-
-    try {
-      console.log(`[InstallGame] Restoring UserData from: ${backupPath}`);
-      await userDataBackup.restoreUserData(backupPath, customAppDir, branch);
-      await userDataBackup.cleanupBackup(backupPath);
-      console.log('[InstallGame] ✓ UserData restored successfully');
-    } catch (restoreError) {
-      console.warn('[InstallGame] ✗ UserData restore failed:', restoreError.message);
-    }
-  } else {
-    console.log('[InstallGame] No backup to restore, empty UserData folder created');
-  }
+  // NEW 2.1.2: No longer create UserData in game installation
+  // UserData is managed in centralized location (getUserDataPath())
+  console.log('[InstallGame] UserData is managed in centralized location');
 
   if (progressCallback) {
     progressCallback('Installation complete', 100, null, null, null);

backend/utils/clientPatcher.js

@@ -147,8 +147,9 @@ class ClientPatcher {
   }
 
   /**
-   * Replace bytes in buffer - only overwrites the length of new bytes
-   * Prevents offset corruption by not expanding the replacement
+   * Replace bytes in buffer with null-padding for shorter replacements
+   * When new pattern is shorter than old, pads with 0x00 to prevent leftover bytes
+   * that can cause memory corruption (free(): invalid pointer) on some systems
    */
   replaceBytes(buffer, oldBytes, newBytes) {
     let count = 0;
@@ -162,7 +163,20 @@ class ClientPatcher {
     const positions = this.findAllOccurrences(result, oldBytes);
 
     for (const pos of positions) {
-      // Only overwrite the length of the new bytes
+      // Log offset and surrounding bytes for debugging
+      const before = result.slice(Math.max(0, pos - 8), pos);
+      const after = result.slice(pos + oldBytes.length, Math.min(result.length, pos + oldBytes.length + 8));
+      console.log(`    Patching at offset 0x${pos.toString(16)} (${pos})`);
+      console.log(`      Before: ${before.toString('hex')}`);
+      console.log(`      Old pattern: ${oldBytes.slice(0, 20).toString('hex')}${oldBytes.length > 20 ? '...' : ''}`);
+      console.log(`      After: ${after.toString('hex')}`);
+
+      // First fill the entire old pattern region with zeros
+      // This prevents leftover bytes from causing memory corruption
+      if (newBytes.length < oldBytes.length) {
+        result.fill(0x00, pos, pos + oldBytes.length);
+      }
+      // Then write the new bytes
       newBytes.copy(result, pos);
       count++;
     }
@@ -170,6 +184,65 @@ class ClientPatcher {
     return { buffer: result, count };
   }
 
+  /**
+   * Replace bytes with skip/limit control (for debugging)
+   * HYTALE_PATCH_SKIP: comma-separated indices to skip (e.g., "0,2" skips 1st and 3rd)
+   * HYTALE_PATCH_LIMIT: max number of patches to apply
+   */
+  replaceBytesLimited(buffer, oldBytes, newBytes, limit) {
+    let count = 0;
+    const result = Buffer.from(buffer);
+
+    if (newBytes.length > oldBytes.length) {
+      console.warn(`  Warning: New pattern (${newBytes.length}) longer than old (${oldBytes.length}), skipping`);
+      return { buffer: result, count: 0 };
+    }
+
+    // Parse skip list from env
+    const skipIndices = (process.env.HYTALE_PATCH_SKIP || '')
+      .split(',')
+      .filter(s => s.trim())
+      .map(s => parseInt(s.trim(), 10));
+    if (skipIndices.length > 0) {
+      console.log(`    Skip indices: ${skipIndices.join(', ')}`);
+    }
+
+    const positions = this.findAllOccurrences(result, oldBytes);
+
+    let patchedCount = 0;
+    for (let i = 0; i < positions.length; i++) {
+      const pos = positions[i];
+
+      // Log offset and surrounding bytes for debugging
+      const before = result.slice(Math.max(0, pos - 8), pos);
+      const after = result.slice(pos + oldBytes.length, Math.min(result.length, pos + oldBytes.length + 8));
+
+      if (skipIndices.includes(i)) {
+        console.log(`    [${i}] Skipping offset 0x${pos.toString(16)} (in skip list)`);
+        continue;
+      }
+
+      if (patchedCount >= limit) {
+        console.log(`    [${i}] Skipping offset 0x${pos.toString(16)} (limit reached)`);
+        continue;
+      }
+
+      console.log(`    [${i}] Patching at offset 0x${pos.toString(16)} (${pos})`);
+      console.log(`      Before: ${before.toString('hex')}`);
+      console.log(`      Old pattern: ${oldBytes.slice(0, 20).toString('hex')}${oldBytes.length > 20 ? '...' : ''}`);
+      console.log(`      After: ${after.toString('hex')}`);
+
+      if (newBytes.length < oldBytes.length) {
+        result.fill(0x00, pos, pos + oldBytes.length);
+      }
+      newBytes.copy(result, pos);
+      patchedCount++;
+      count++;
+    }
+
+    return { buffer: result, count };
+  }
+
   /**
    * UTF-8 domain replacement for Java JAR files.
    * Java stores strings in UTF-8 format in the constant pool.
@@ -197,11 +270,19 @@ class ClientPatcher {
    * .NET AOT stores some strings in various formats:
    * - Standard UTF-16LE (each char is 2 bytes with \x00 high byte)
    * - Length-prefixed where last char may have metadata byte instead of \x00
+   *
+   * IMPORTANT: newDomain must be same length or shorter than oldDomain to avoid buffer overflow
    */
   findAndReplaceDomainSmart(data, oldDomain, newDomain) {
     let count = 0;
     const result = Buffer.from(data);
 
+    // Safety check: new domain must not be longer than old
+    if (newDomain.length > oldDomain.length) {
+      console.warn(`  Warning: New domain (${newDomain.length} chars) longer than old (${oldDomain.length} chars), skipping smart replacement`);
+      return { buffer: result, count: 0 };
+    }
+
     const oldUtf16NoLast = this.stringToUtf16LE(oldDomain.slice(0, -1));
     const newUtf16NoLast = this.stringToUtf16LE(newDomain.slice(0, -1));
 
@@ -217,6 +298,11 @@ class ClientPatcher {
       const lastCharFirstByte = result[lastCharPos];
 
       if (lastCharFirstByte === oldLastCharByte) {
+        // Zero-fill the old region first if new is shorter
+        if (newUtf16NoLast.length < oldUtf16NoLast.length) {
+          result.fill(0x00, pos, pos + oldUtf16NoLast.length);
+        }
+
         newUtf16NoLast.copy(result, pos);
 
         result[lastCharPos] = newLastCharByte;
@@ -239,6 +325,10 @@ class ClientPatcher {
   /**
    * Apply all domain patches using length-prefixed format
    * This is the main patching method for variable-length domains
+   *
+   * Debug env vars:
+   *   HYTALE_SKIP_SENTRY_PATCH=1 - Skip sentry URL patch (biggest size change)
+   *   HYTALE_SKIP_SUBDOMAIN_PATCH=1 - Skip subdomain prefix patches
    */
   applyDomainPatches(data, domain, protocol = 'https://') {
     let result = Buffer.from(data);
@@ -247,50 +337,79 @@ class ClientPatcher {
 
     console.log(`  Patching strategy: ${strategy.description}`);
 
-    // 1. Patch telemetry/sentry URL
-    const oldSentry = 'https://ca900df42fcf57d4dd8401a86ddd7da2@sentry.hytale.com/2';
-    const newSentry = `${protocol}t@${domain}/2`;
+    // 1. Patch telemetry/sentry URL (skip if debugging)
+    if (process.env.HYTALE_SKIP_SENTRY_PATCH === '1') {
+      console.log(`  Skipping sentry patch (HYTALE_SKIP_SENTRY_PATCH=1)`);
+    } else {
+      const oldSentry = 'https://ca900df42fcf57d4dd8401a86ddd7da2@sentry.hytale.com/2';
+      const newSentry = `${protocol}t@${domain}/2`;
 
-    console.log(`  Patching sentry: ${oldSentry.slice(0, 30)}... -> ${newSentry}`);
-    const sentryResult = this.replaceBytes(
-        result,
-        this.stringToLengthPrefixed(oldSentry),
-        this.stringToLengthPrefixed(newSentry)
-    );
-    result = sentryResult.buffer;
-    if (sentryResult.count > 0) {
-      console.log(`    Replaced ${sentryResult.count} sentry occurrence(s)`);
-      totalCount += sentryResult.count;
+      console.log(`  Patching sentry: ${oldSentry.slice(0, 30)}... -> ${newSentry}`);
+      const sentryResult = this.replaceBytes(
+          result,
+          this.stringToLengthPrefixed(oldSentry),
+          this.stringToLengthPrefixed(newSentry)
+      );
+      result = sentryResult.buffer;
+      if (sentryResult.count > 0) {
+        console.log(`    Replaced ${sentryResult.count} sentry occurrence(s)`);
+        totalCount += sentryResult.count;
+      }
     }
 
     // 2. Patch main domain (hytale.com -> mainDomain)
+    // Try length-prefixed format first, then fall back to pure UTF-16LE
     console.log(`  Patching domain: ${ORIGINAL_DOMAIN} -> ${strategy.mainDomain}`);
-    const domainResult = this.replaceBytes(
-        result,
-        this.stringToLengthPrefixed(ORIGINAL_DOMAIN),
-        this.stringToLengthPrefixed(strategy.mainDomain)
-    );
+
+    // Check for HYTALE_PATCH_MODE env var to test different formats
+    const patchMode = process.env.HYTALE_PATCH_MODE || 'length-prefixed';
+    console.log(`  Patch mode: ${patchMode}`);
+
+    let domainResult;
+    if (patchMode === 'utf16le') {
+      // Pure UTF-16LE replacement (no length prefix)
+      const oldUtf16 = this.stringToUtf16LE(ORIGINAL_DOMAIN);
+      const newUtf16 = this.stringToUtf16LE(strategy.mainDomain);
+      console.log(`    UTF-16LE: old=${oldUtf16.length} bytes, new=${newUtf16.length} bytes`);
+
+      // HYTALE_PATCH_LIMIT: only patch first N occurrences (for debugging)
+      const patchLimit = parseInt(process.env.HYTALE_PATCH_LIMIT || '999', 10);
+      console.log(`    Patch limit: ${patchLimit}`);
+      domainResult = this.replaceBytesLimited(result, oldUtf16, newUtf16, patchLimit);
+    } else {
+      // Length-prefixed format (default)
+      domainResult = this.replaceBytes(
+          result,
+          this.stringToLengthPrefixed(ORIGINAL_DOMAIN),
+          this.stringToLengthPrefixed(strategy.mainDomain)
+      );
+    }
+
     result = domainResult.buffer;
     if (domainResult.count > 0) {
       console.log(`    Replaced ${domainResult.count} domain occurrence(s)`);
       totalCount += domainResult.count;
     }
 
-    // 3. Patch subdomain prefixes
-    const subdomains = ['https://tools.', 'https://sessions.', 'https://account-data.', 'https://telemetry.'];
-    const newSubdomainPrefix = protocol + strategy.subdomainPrefix;
+    // 3. Patch subdomain prefixes (skip if debugging)
+    if (process.env.HYTALE_SKIP_SUBDOMAIN_PATCH === '1') {
+      console.log(`  Skipping subdomain patches (HYTALE_SKIP_SUBDOMAIN_PATCH=1)`);
+    } else {
+      const subdomains = ['https://tools.', 'https://sessions.', 'https://account-data.', 'https://telemetry.'];
+      const newSubdomainPrefix = protocol + strategy.subdomainPrefix;
 
-    for (const sub of subdomains) {
-      console.log(`  Patching subdomain: ${sub} -> ${newSubdomainPrefix}`);
-      const subResult = this.replaceBytes(
-          result,
-          this.stringToLengthPrefixed(sub),
-          this.stringToLengthPrefixed(newSubdomainPrefix)
-      );
-      result = subResult.buffer;
-      if (subResult.count > 0) {
-        console.log(`    Replaced ${subResult.count} occurrence(s)`);
-        totalCount += subResult.count;
+      for (const sub of subdomains) {
+        console.log(`  Patching subdomain: ${sub} -> ${newSubdomainPrefix}`);
+        const subResult = this.replaceBytes(
+            result,
+            this.stringToLengthPrefixed(sub),
+            this.stringToLengthPrefixed(newSubdomainPrefix)
+        );
+        result = subResult.buffer;
+        if (subResult.count > 0) {
+          console.log(`    Replaced ${subResult.count} occurrence(s)`);
+          totalCount += subResult.count;
+        }
       }
     }
 
@@ -298,38 +417,13 @@ class ClientPatcher {
   }
 
   /**
-   * Patch Discord invite URLs from .gg/hytale to .gg/MHkEjepMQ7
+   * Patch Discord invite URLs - DISABLED
+   * Was causing buffer overflow crashes on Steam Deck/Ubuntu LTS
+   * The Discord URL in the game doesn't affect F2P functionality anyway
    */
   patchDiscordUrl(data) {
-    let count = 0;
-    const result = Buffer.from(data);
-
-    const oldUrl = '.gg/hytale';
-    const newUrl = '.gg/MHkEjepMQ7';
-
-    // Try length-prefixed format first
-    const lpResult = this.replaceBytes(
-        result,
-        this.stringToLengthPrefixed(oldUrl),
-        this.stringToLengthPrefixed(newUrl)
-    );
-
-    if (lpResult.count > 0) {
-      return { buffer: lpResult.buffer, count: lpResult.count };
-    }
-
-    // Fallback to UTF-16LE
-    const oldUtf16 = this.stringToUtf16LE(oldUrl);
-    const newUtf16 = this.stringToUtf16LE(newUrl);
-
-    const positions = this.findAllOccurrences(result, oldUtf16);
-
-    for (const pos of positions) {
-      newUtf16.copy(result, pos);
-      count++;
-    }
-
-    return { buffer: result, count };
+    // Disabled - no practical effect and was causing memory corruption
+    return { buffer: Buffer.from(data), count: 0 };
   }
 
   /**
@@ -483,6 +577,14 @@ class ClientPatcher {
       progressCallback('Patching domain references...', 50);
     }
 
+    // HYTALE_NOOP_TEST: Just read and write binary without any changes
+    if (process.env.HYTALE_NOOP_TEST === '1') {
+      console.log('NOOP TEST: Writing binary without modifications...');
+      fs.writeFileSync(clientPath, data);
+      this.markAsPatched(clientPath);
+      return { success: true, patchCount: 0, noop: true };
+    }
+
     console.log('Applying domain patches (length-prefixed format)...');
     const { buffer: patchedData, count } = this.applyDomainPatches(data, newDomain);
 
@@ -490,6 +592,17 @@ class ClientPatcher {
     const { buffer: finalData, count: discordCount } = this.patchDiscordUrl(patchedData);
 
     if (count === 0 && discordCount === 0) {
+      // Check if we're in debug mode with skip - don't fallback if intentionally skipping
+      const hasSkipList = (process.env.HYTALE_PATCH_SKIP || '').trim().length > 0;
+      const noLegacyFallback = process.env.HYTALE_NO_LEGACY_FALLBACK === '1';
+
+      if (hasSkipList || noLegacyFallback) {
+        console.log('No occurrences patched (skip list active or legacy fallback disabled)');
+        fs.writeFileSync(clientPath, patchedData);
+        this.markAsPatched(clientPath);
+        return { success: true, patchCount: 0, skipped: true };
+      }
+
       console.log('No occurrences found - trying legacy UTF-16LE format...');
 
       // Fallback to legacy patching for older binary formats

backend/utils/userDataBackup.js

@@ -46,7 +46,8 @@ class UserDataBackup {
       console.log(`[UserDataBackup] Copying from ${userDataPath} to ${backupPath}...`);
       await fs.copy(userDataPath, backupPath, {
         overwrite: true,
-        errorOnExist: false
+        errorOnExist: false,
+        dereference: true  // Follow symlinks to avoid EPERM errors on Windows
       });
       console.log('[UserDataBackup] ✓ Backup completed successfully');
       return backupPath;
@@ -82,7 +83,8 @@ class UserDataBackup {
 
       await fs.copy(backupPath, userDataPath, {
         overwrite: true,
-        errorOnExist: false
+        errorOnExist: false,
+        dereference: true  // Follow symlinks to avoid EPERM errors on Windows
       });
       
       console.log('UserData restore completed successfully');

backend/utils/userDataMigration.js

@@ -0,0 +1,172 @@
+const fs = require('fs-extra');
+const path = require('path');
+const { getHytaleSavesDir, getResolvedAppDir } = require('../core/paths');
+const { loadConfig, saveConfig } = require('../core/config');
+
+/**
+ * NEW SYSTEM (2.1.2+): UserData Migration to Centralized Location
+ * 
+ * UserData is now stored in a centralized location instead of inside game installation:
+ * - Windows: %LOCALAPPDATA%\HytaleSaves\
+ * - macOS: ~/Library/Application Support/HytaleSaves/
+ * - Linux: ~/.hytalesaves/
+ * 
+ * This eliminates the need for backup/restore during updates.
+ */
+
+/**
+ * Check if migration to centralized UserData has been completed
+ */
+function isMigrationCompleted() {
+  const config = loadConfig();
+  return config.userDataMigrated === true;
+}
+
+/**
+ * Mark migration as completed
+ */
+function markMigrationCompleted() {
+  saveConfig({ userDataMigrated: true });
+  console.log('[UserDataMigration] Migration marked as completed in config');
+}
+
+/**
+ * Find old UserData location (pre-2.1.2)
+ * Searches in: installPath/branch/package/game/latest/Client/UserData
+ */
+function findOldUserDataPath() {
+  try {
+    const config = loadConfig();
+    const installPath = getResolvedAppDir();
+    const branch = config.version_branch || 'release';
+    
+    console.log(`[UserDataMigration] Looking for old UserData...`);
+    console.log(`[UserDataMigration]   Install path: ${installPath}`);
+    console.log(`[UserDataMigration]   Branch: ${branch}`);
+    
+    // Old location
+    const oldPath = path.join(installPath, branch, 'package', 'game', 'latest', 'Client', 'UserData');
+    console.log(`[UserDataMigration]   Checking: ${oldPath}`);
+    console.log(`[UserDataMigration]   Checking: ${oldPath}`);
+    
+    if (fs.existsSync(oldPath)) {
+      console.log(`[UserDataMigration] ✓ Found old UserData at: ${oldPath}`);
+      return oldPath;
+    }
+    
+    console.log(`[UserDataMigration] ✗ Not found at current branch location`);
+    
+    // Try other branch if current doesn't exist
+    const otherBranch = branch === 'release' ? 'pre-release' : 'release';
+    const otherPath = path.join(installPath, otherBranch, 'package', 'game', 'latest', 'Client', 'UserData');
+    console.log(`[UserDataMigration]   Checking other branch: ${otherPath}`);
+    console.log(`[UserDataMigration]   Checking other branch: ${otherPath}`);
+    
+    if (fs.existsSync(otherPath)) {
+      console.log(`[UserDataMigration] ✓ Found old UserData in other branch at: ${otherPath}`);
+      return otherPath;
+    }
+    
+    console.log('[UserDataMigration] ✗ No old UserData found in any branch');
+    return null;
+  } catch (error) {
+    console.error('[UserDataMigration] Error finding old UserData:', error);
+    return null;
+  }
+}
+
+/**
+ * Migrate UserData from old location to new centralized location
+ * One-time operation when upgrading to 2.1.2
+ */
+async function migrateUserDataToCentralized() {
+  // Check if already migrated
+  if (isMigrationCompleted()) {
+    console.log('[UserDataMigration] Migration already completed, skipping');
+    return { success: true, alreadyMigrated: true };
+  }
+  
+  console.log('[UserDataMigration] === Starting UserData Migration to Centralized Location ===');
+  
+  const newUserDataPath = getHytaleSavesDir();
+  console.log(`[UserDataMigration] Target location: ${newUserDataPath}`);
+  
+  // Ensure new directory exists
+  if (!fs.existsSync(newUserDataPath)) {
+    fs.mkdirSync(newUserDataPath, { recursive: true });
+    console.log('[UserDataMigration] Created new HytaleSaves directory');
+  }
+  
+  // Find old UserData
+  const oldUserDataPath = findOldUserDataPath();
+  
+  if (!oldUserDataPath) {
+    console.log('[UserDataMigration] No old UserData found - fresh install or already migrated');
+    // Don't mark as migrated - let it check again next time in case game gets installed later
+    return { success: true, freshInstall: true };
+  }
+  
+  // Check if new location already has data (shouldn't happen, but safety check)
+  const existingFiles = fs.readdirSync(newUserDataPath);
+  if (existingFiles.length > 0) {
+    console.warn('[UserDataMigration] New location already contains files, marking as migrated to avoid re-attempts');
+    markMigrationCompleted();
+    return { success: true, skipped: true, reason: 'target_not_empty' };
+  }
+  
+  try {
+    console.log(`[UserDataMigration] Copying from ${oldUserDataPath} to ${newUserDataPath}...`);
+    
+    // Copy all UserData to new location
+    await fs.copy(oldUserDataPath, newUserDataPath, {
+      overwrite: false,
+      errorOnExist: false,
+      dereference: true  // Follow symlinks to avoid EPERM errors on Windows
+    });
+    
+    console.log('[UserDataMigration] ✓ UserData copied successfully');
+    
+    // Mark migration as completed
+    markMigrationCompleted();
+    
+    console.log('[UserDataMigration] === Migration Completed Successfully ===');
+    return { 
+      success: true, 
+      migrated: true,
+      from: oldUserDataPath,
+      to: newUserDataPath
+    };
+    
+  } catch (error) {
+    console.error('[UserDataMigration] ✗ Migration failed:', error);
+    return { 
+      success: false, 
+      error: error.message,
+      from: oldUserDataPath,
+      to: newUserDataPath
+    };
+  }
+}
+
+/**
+ * Get the centralized UserData path (always use this in 2.1.2+)
+ * Ensures directory exists
+ */
+function getUserDataPath() {
+  const userDataPath = getHytaleSavesDir();
+  
+  // Ensure directory exists
+  if (!fs.existsSync(userDataPath)) {
+    fs.mkdirSync(userDataPath, { recursive: true });
+    console.log(`[UserDataMigration] Created UserData directory: ${userDataPath}`);
+  }
+  
+  return userDataPath;
+}
+
+module.exports = {
+  migrateUserDataToCentralized,
+  getUserDataPath,
+  isMigrationCompleted,
+  findOldUserDataPath
+};

main.js

@@ -5,6 +5,7 @@ const { autoUpdater } = require('electron-updater');
 const fs = require('fs');
 const { launchGame, launchGameWithVersionCheck, installGame, saveUsername, loadUsername, saveChatUsername, loadChatUsername, saveChatColor, loadChatColor, saveJavaPath, loadJavaPath, saveInstallPath, loadInstallPath, saveDiscordRPC, loadDiscordRPC, saveLanguage, loadLanguage, saveCloseLauncherOnStart, loadCloseLauncherOnStart, saveLauncherHardwareAcceleration, loadLauncherHardwareAcceleration, isGameInstalled, uninstallGame, repairGame, getHytaleNews, handleFirstLaunchCheck, proposeGameUpdate, markAsLaunched } = require('./backend/launcher');
 const { retryPWRDownload } = require('./backend/managers/gameManager');
+const { migrateUserDataToCentralized } = require('./backend/utils/userDataMigration');
 
 // Handle Hardware Acceleration
 try {
@@ -298,6 +299,14 @@ app.whenReady().then(async () => {
   // Initialize Profile Manager (runs migration if needed)
   profileManager.init();
 
+  // Migrate UserData to centralized location (v2.1.2+)
+  console.log('[Startup] Checking UserData migration...');
+  try {
+    await migrateUserDataToCentralized();
+  } catch (error) {
+    console.error('[Startup] UserData migration failed:', error);
+  }
+
   createSplashScreen();
 
   setTimeout(async () => {

package.json

@@ -1,6 +1,6 @@
 {
   "name": "hytale-f2p-launcher",
-  "version": "2.1.1",
+  "version": "2.1.2",
   "description": "A modern, cross-platform launcher for Hytale with automatic updates and multi-client support",
   "homepage": "https://github.com/amiayweb/Hytale-F2P",
   "main": "main.js",