diff --git a/README.md b/README.md
index 4a2556c..88e5ef7 100644
--- a/README.md
+++ b/README.md
@@ -10,6 +10,23 @@ The target design is deny-by-default:
 - Games must be explicitly enabled before PatchDL checks or downloads updates.
 - Patch selection is capped to the highest update compatible with the current
   firmware.
+- Install actions are source-aware: shadowmounted and unknown titles are never
+  installed by PatchDL.
+
+## Source Classification
+
+PatchDL treats the title source as part of the safety policy:
+
+```text
+official     check/download/install allowed
+external     check/download/install allowed when detected as a real install
+shadowmount  check/download allowed, install blocked
+unknown      check allowed, download/install blocked
+```
+
+The future ELF scanner should classify titles by app metadata plus mount table
+inspection. Shadowmounts should be detected through `statfs()` / `getfsstat()`
+and `nullfs` mount origins instead of trusting title IDs alone.
 
 ## Current Contents
 
@@ -20,4 +37,3 @@ web/
 
 Open `web/index.html` directly for the mock UI, or serve `web/` from a local
 HTTP server.
-
diff --git a/web/README.md b/web/README.md
index b452759..7df5375 100644
--- a/web/README.md
+++ b/web/README.md
@@ -28,6 +28,12 @@ The UI assumes deny-by-default behavior:
   "download_dir": "/mnt/usb0/patches",
   "install_after_download": false,
   "delete_pkg_after_install": false,
+  "source_policy": {
+    "official": { "allow_check": true, "allow_download": true, "allow_install": true },
+    "external": { "allow_check": true, "allow_download": true, "allow_install": true },
+    "shadowmount": { "allow_check": true, "allow_download": true, "allow_install": false },
+    "unknown": { "allow_check": true, "allow_download": false, "allow_install": false }
+  },
   "cdn_allowlist": [
     "sgst.prod.dl.playstation.net",
     "gst.prod.dl.playstation.net",
@@ -45,3 +51,30 @@ latest_compatible
 pin
 check_only
 ```
+
+Per-title source fields:
+
+```json
+{
+  "title_id": "PPSA90001_00",
+  "name": "Shadowmounted Test Title",
+  "source_type": "shadowmount",
+  "source_path": "/system_ex/app/PPSA90001_00",
+  "mount_from": "/mnt/usb0/itemzflow/Shadowmounted Test Title",
+  "enabled": true,
+  "mode": "download_only"
+}
+```
+
+Supported `source_type` values:
+
+```text
+official
+external
+shadowmount
+unknown
+```
+
+The frontend treats `shadowmount` as download-only and `unknown` as blocked for
+downloads and installs. Backend code should enforce the same policy even if a
+client sends a forged request.
diff --git a/web/app.js b/web/app.js
index 44e8286..3f3fb90 100644
--- a/web/app.js
+++ b/web/app.js
@@ -6,6 +6,33 @@ const API = {
   action: (titleId, action) => `/api/titles/${encodeURIComponent(titleId)}/${action}`,
 };
 
+const SOURCE_TYPES = {
+  official: {
+    label: "Official",
+    className: "ok",
+    installAllowed: true,
+    description: "Echte Installation",
+  },
+  external: {
+    label: "External",
+    className: "external",
+    installAllowed: true,
+    description: "Echte externe Installation",
+  },
+  shadowmount: {
+    label: "Shadowmount",
+    className: "shadow",
+    installAllowed: false,
+    description: "Download only",
+  },
+  unknown: {
+    label: "Unknown",
+    className: "blocked",
+    installAllowed: false,
+    description: "Blockiert",
+  },
+};
+
 const fallback = {
   status: {
     firmware: "11.60",
@@ -20,6 +47,12 @@ const fallback = {
     download_dir: "/mnt/usb0/patches",
     install_after_download: false,
     delete_pkg_after_install: false,
+    source_policy: {
+      official: { allow_check: true, allow_download: true, allow_install: true },
+      external: { allow_check: true, allow_download: true, allow_install: true },
+      shadowmount: { allow_check: true, allow_download: true, allow_install: false },
+      unknown: { allow_check: true, allow_download: false, allow_install: false },
+    },
     cdn_allowlist: [
       "sgst.prod.dl.playstation.net",
       "gst.prod.dl.playstation.net",
@@ -35,6 +68,9 @@ const fallback = {
       compatible_version: "01.041.000",
       latest_version: "01.041.000",
       latest_required_fw: "11.60",
+      source_type: "official",
+      source_path: "/system_ex/app/PPSA01628_00",
+      mount_from: "/dev/ssd0.system_ex",
       enabled: true,
       mode: "latest_compatible",
       queued: false,
@@ -48,6 +84,9 @@ const fallback = {
       compatible_version: "01.004.000",
       latest_version: "01.004.000",
       latest_required_fw: "10.01",
+      source_type: "external",
+      source_path: "/system_data/priv/appmeta/external/PPSA01284_00",
+      mount_from: "/mnt/ext0/user/app/PPSA01284_00",
       enabled: true,
       mode: "pin",
       max_content_ver: "01.004.000",
@@ -62,11 +101,30 @@ const fallback = {
       compatible_version: null,
       latest_version: "01.012.000",
       latest_required_fw: "12.50",
+      source_type: "unknown",
+      source_path: "/system_ex/app/PPSA08329_00",
+      mount_from: "",
       enabled: false,
       mode: "disabled",
       queued: false,
       status: "blocked",
     },
+    {
+      title_id: "PPSA90001_00",
+      name: "Shadowmounted Test Title",
+      content_id: "UP0000-PPSA90001_00-SHADOWMOUNT0001",
+      installed_version: "01.000.000",
+      compatible_version: "01.006.000",
+      latest_version: "01.009.000",
+      latest_required_fw: "12.00",
+      source_type: "shadowmount",
+      source_path: "/system_ex/app/PPSA90001_00",
+      mount_from: "/mnt/usb0/itemzflow/Shadowmounted Test Title",
+      enabled: true,
+      mode: "download_only",
+      queued: false,
+      status: "available",
+    },
   ],
   downloads: [
     {
@@ -116,6 +174,7 @@ function bindElements() {
     queueList: document.getElementById("queueList"),
     logOutput: document.getElementById("logOutput"),
     allowlistHosts: document.getElementById("allowlistHosts"),
+    sourcePolicyList: document.getElementById("sourcePolicyList"),
     searchInput: document.getElementById("searchInput"),
     defaultPolicy: document.getElementById("defaultPolicy"),
     downloadDir: document.getElementById("downloadDir"),
@@ -207,6 +266,7 @@ function renderSettings() {
     chip.textContent = host;
     return chip;
   }));
+  renderSourcePolicies();
 }
 
 function renderGames() {
@@ -227,6 +287,7 @@ function renderGames() {
 function matchesFilter(game) {
   if (state.filter === "enabled") return game.enabled;
   if (state.filter === "available") return game.status === "available";
+  if (state.filter === "shadowmount") return sourceType(game) === "shadowmount";
   if (state.filter === "blocked") return game.status === "blocked";
   if (state.filter === "queued") return game.queued || game.status === "queued";
   return true;
@@ -235,6 +296,7 @@ function matchesFilter(game) {
 function matchesQuery(game) {
   if (!state.query) return true;
   return [game.name, game.title_id, game.content_id]
+    .concat([game.source_type, game.source_path, game.mount_from])
     .filter(Boolean)
     .some((value) => value.toLowerCase().includes(state.query));
 }
@@ -245,6 +307,7 @@ function createGameCard(game) {
 
   const title = document.createElement("div");
   title.className = "game-title";
+  const installBlocked = isInstallBlocked(game);
   title.innerHTML = `
     <div class="cover">${initials(game.name)}</div>
     <div>
@@ -255,8 +318,11 @@ function createGameCard(game) {
       </div>
       <div class="subline" style="margin-top:8px">
         ${statusPill(game)}
+        ${sourcePill(game)}
+        ${installBlocked ? `<span class="pill blocked">Install gesperrt</span>` : `<span class="pill ok">Install erlaubt</span>`}
         <span class="pill">${game.enabled ? "Aktiv" : "Aus"}</span>
       </div>
+      <div class="source-path">${escapeHtml(sourceDetail(game))}</div>
     </div>
   `;
 
@@ -306,7 +372,7 @@ function createGameCard(game) {
       <svg><use href="#icon-refresh"></use></svg>
       Pruefen
     </button>
-    <button class="row-button is-primary" data-action="download" ${!game.compatible_version ? "disabled" : ""}>
+    <button class="row-button is-primary" data-action="download" ${!isDownloadAllowed(game) ? "disabled" : ""} title="${escapeHtml(downloadTitle(game))}">
       <svg><use href="#icon-download"></use></svg>
       Laden
     </button>
@@ -331,12 +397,39 @@ function versionBox(label, value) {
 }
 
 function statusPill(game) {
-  if (game.status === "blocked") return `<span class="pill blocked">FW blockiert</span>`;
+  if (game.status === "blocked") return `<span class="pill blocked">${escapeHtml(blockedLabel(game))}</span>`;
   if (game.status === "queued") return `<span class="pill warn">In Queue</span>`;
   if (game.status === "available") return `<span class="pill ok">Update verfuegbar</span>`;
   return `<span class="pill">Aktuell</span>`;
 }
 
+function sourcePill(game) {
+  const info = sourceInfo(game);
+  return `<span class="pill ${info.className}">${escapeHtml(info.label)}</span>`;
+}
+
+function sourceInfo(game) {
+  return SOURCE_TYPES[sourceType(game)] || SOURCE_TYPES.unknown;
+}
+
+function sourceType(game) {
+  return game.source_type || "unknown";
+}
+
+function sourceDetail(game) {
+  const src = sourceType(game);
+  if (src === "shadowmount") return `Mount: ${game.mount_from || "unbekannte Quelle"}`;
+  if (src === "external") return `External: ${game.source_path || "externe App-Metadaten"}`;
+  if (src === "official") return game.source_path || "Offizielle Installation";
+  return "Quelle nicht eindeutig erkannt";
+}
+
+function blockedLabel(game) {
+  if (sourceType(game) === "unknown") return "Quelle unbekannt";
+  if (!game.compatible_version) return "FW blockiert";
+  return "Blockiert";
+}
+
 function renderQueue() {
   els.queueList.replaceChildren();
   if (!state.downloads.length) {
@@ -362,6 +455,22 @@ function renderQueue() {
   });
 }
 
+function renderSourcePolicies() {
+  const rows = Object.keys(SOURCE_TYPES).map((type) => {
+    const info = SOURCE_TYPES[type];
+    const policy = sourcePolicyForType(type);
+    const row = document.createElement("div");
+    row.className = "policy-row";
+    row.innerHTML = `
+      <span class="pill ${info.className}">${escapeHtml(info.label)}</span>
+      <strong>${policy.allow_install ? "Install erlaubt" : "Install gesperrt"}</strong>
+      <em>${policy.allow_download ? "Download erlaubt" : "Download gesperrt"} - ${escapeHtml(info.description)}</em>
+    `;
+    return row;
+  });
+  els.sourcePolicyList.replaceChildren(...rows);
+}
+
 function renderLogs() {
   els.logOutput.textContent = state.logs.join("\n");
 }
@@ -391,6 +500,11 @@ async function runTitleAction(titleId, action) {
   const game = state.titles.find((item) => item.title_id === titleId);
   if (!game) return;
 
+  if (action === "download" && !isDownloadAllowed(game)) {
+    showToast(downloadTitle(game));
+    return;
+  }
+
   try {
     await postJson(API.action(titleId, action), {});
   } catch (error) {
@@ -398,6 +512,9 @@ async function runTitleAction(titleId, action) {
   }
 
   if (action === "download" && game.compatible_version) {
+    const detail = isInstallBlocked(game)
+      ? "Download only - Install durch Source-Policy gesperrt"
+      : "Wartet auf Start";
     game.queued = true;
     game.status = "queued";
     if (!state.downloads.some((item) => item.title_id === titleId)) {
@@ -406,10 +523,10 @@ async function runTitleAction(titleId, action) {
         name: game.name,
         version: game.compatible_version,
         progress: 0,
-        detail: "Wartet auf Start",
+        detail,
       });
     }
-    state.logs.push(`[${timeNow()}] Queued ${game.title_id} ${game.compatible_version}`);
+    state.logs.push(`[${timeNow()}] Queued ${game.title_id} ${game.compatible_version} (${sourceType(game)}, install=${isInstallBlocked(game) ? "blocked" : "allowed"})`);
     showToast(`${game.title_id} wurde zur Queue hinzugefuegt.`);
   } else {
     state.logs.push(`[${timeNow()}] Check requested for ${game.title_id}`);
@@ -424,6 +541,11 @@ async function runTitleAction(titleId, action) {
 function updateGame(titleId, patch) {
   const game = state.titles.find((item) => item.title_id === titleId);
   if (!game) return;
+  if (sourceType(game) === "unknown" && patch.mode && !["disabled", "check_only"].includes(patch.mode)) {
+    patch.mode = "check_only";
+    patch.enabled = true;
+    showToast(`${titleId}: Quelle unbekannt, nur Check only erlaubt.`);
+  }
   Object.assign(game, patch);
   if (patch.mode === "disabled") game.enabled = false;
   state.logs.push(`[${timeNow()}] Policy updated for ${titleId}`);
@@ -431,6 +553,33 @@ function updateGame(titleId, patch) {
   renderLogs();
 }
 
+function isDownloadAllowed(game) {
+  const policy = sourcePolicy(game);
+  return Boolean(game.enabled && game.compatible_version && policy.allow_download);
+}
+
+function isInstallBlocked(game) {
+  return !sourcePolicy(game).allow_install;
+}
+
+function sourcePolicy(game) {
+  return sourcePolicyForType(sourceType(game));
+}
+
+function sourcePolicyForType(type) {
+  const fallbackPolicy = fallback.config.source_policy[type] || fallback.config.source_policy.unknown;
+  const configuredPolicy = (state.config.source_policy || {})[type] || {};
+  return { ...fallbackPolicy, ...configuredPolicy };
+}
+
+function downloadTitle(game) {
+  if (!game.enabled) return "Titel ist deaktiviert.";
+  if (!game.compatible_version) return "Keine kompatible Update-Version verfuegbar.";
+  if (!sourcePolicy(game).allow_download) return "Download ist fuer diese Quelle gesperrt.";
+  if (isInstallBlocked(game)) return "Download erlaubt, Installation bleibt fuer diese Quelle gesperrt.";
+  return "Kompatibles Update laden.";
+}
+
 async function postJson(url, body) {
   const response = await fetch(url, {
     method: "POST",
diff --git a/web/index.html b/web/index.html
index b7b80fa..9b2d9be 100644
--- a/web/index.html
+++ b/web/index.html
@@ -127,6 +127,7 @@
             <button class="is-selected" data-filter="all">Alle</button>
             <button data-filter="enabled">Aktiv</button>
             <button data-filter="available">Updates</button>
+            <button data-filter="shadowmount">Shadow</button>
             <button data-filter="blocked">Blockiert</button>
             <button data-filter="queued">Queue</button>
           </div>
@@ -189,6 +190,11 @@
               <span>Interne CDN Allowlist</span>
               <div id="allowlistHosts"></div>
             </div>
+
+            <div class="source-policy">
+              <span>Install Schutz</span>
+              <div id="sourcePolicyList"></div>
+            </div>
           </div>
         </section>
 
diff --git a/web/styles.css b/web/styles.css
index 4ee9c0f..bd6f369 100644
--- a/web/styles.css
+++ b/web/styles.css
@@ -377,12 +377,34 @@ h2 {
   color: #81500b;
 }
 
+.pill.external {
+  border-color: #b7d8e8;
+  background: var(--blue-soft);
+  color: #1e547a;
+}
+
+.pill.shadow {
+  border-color: #d0c4eb;
+  background: #eee8fb;
+  color: #584080;
+}
+
 .pill.blocked {
   border-color: #f0b8b8;
   background: var(--red-soft);
   color: var(--red);
 }
 
+.source-path {
+  margin-top: 8px;
+  max-width: 100%;
+  overflow: hidden;
+  color: var(--muted);
+  font-size: 12px;
+  text-overflow: ellipsis;
+  white-space: nowrap;
+}
+
 .version-grid {
   display: grid;
   grid-template-columns: repeat(3, minmax(0, 1fr));
@@ -521,7 +543,8 @@ h2 {
 }
 
 .field span,
-.allowlist > span {
+.allowlist > span,
+.source-policy > span {
   color: var(--muted);
   font-size: 12px;
   font-weight: 700;
@@ -576,12 +599,47 @@ h2 {
   margin-top: 14px;
 }
 
+.source-policy {
+  display: grid;
+  gap: 8px;
+  margin-top: 14px;
+}
+
 .allowlist div {
   display: flex;
   flex-wrap: wrap;
   gap: 6px;
 }
 
+.source-policy > div {
+  display: grid;
+  gap: 8px;
+}
+
+.policy-row {
+  display: grid;
+  grid-template-columns: 110px minmax(100px, 0.8fr) minmax(0, 1fr);
+  gap: 8px;
+  align-items: center;
+  padding: 8px;
+  background: #f8f9f6;
+  border: 1px solid var(--border);
+  border-radius: 8px;
+}
+
+.policy-row strong {
+  font-size: 13px;
+}
+
+.policy-row em {
+  overflow: hidden;
+  color: var(--muted);
+  font-size: 12px;
+  font-style: normal;
+  text-overflow: ellipsis;
+  white-space: nowrap;
+}
+
 .host-chip {
   display: inline-flex;
   align-items: center;
@@ -701,10 +759,15 @@ pre {
   .toolbar,
   .split-band,
   .status-strip,
-  .version-grid {
+  .version-grid,
+  .policy-row {
     grid-template-columns: 1fr;
   }
 
+  .policy-row em {
+    white-space: normal;
+  }
+
   .segmented {
     overflow-x: auto;
   }