diff --git a/ota/h5/index-v6.html b/ota/h5/index-v6.html
index aace6e8..8aae133 100644
--- a/ota/h5/index-v6.html
+++ b/ota/h5/index-v6.html
@@ -20,26 +20,24 @@ h1{font-size:20px;color:#fff;margin:0}
  <h1>Yuzu GCA <span class="badge">v6</span></h1>
  <div class="sub">热更新 v6 — 渠道选择器</div>
 </header>
-
 <div class="card">
  <div class="card-title">更新渠道</div>
  <div class="chip-row">
-  <div id="ch-stable" class="chip chip-on" onclick="selectCh('stable')">Stable</div>
-  <div id="ch-beta" class="chip chip-off" onclick="selectCh('beta')">Beta</div>
-  <div id="ch-nightly" class="chip chip-off" onclick="selectCh('nightly')">Nightly</div>
+  <div class="chip chip-on" onclick="selectCh(this,'stable')">Stable</div>
+  <div class="chip chip-off" onclick="selectCh(this,'beta')">Beta</div>
+  <div class="chip chip-off" onclick="selectCh(this,'nightly')">Nightly</div>
  </div>
 </div>
-
 <button class="btn btn-check" onclick="checkUpdate()">检查更新</button>
 <button class="btn btn-download" onclick="applyUpdate()" id="btnApply" disabled>下载更新</button>
 <div class="log" id="log"></div>
 <script>
-var dlUrl='',dlVer='';
+var dlUrl='',dlVer='',dlSha='';
 var BASE='https://git.childish-ghost.com/LukeMackin/Yuzu-GCA/raw/branch/main/ota';
 
-function selectCh(ch){
+function selectCh(el,ch){
  document.querySelectorAll('.chip').forEach(function(c){c.className='chip chip-off'});
- document.getElementById('ch-'+ch).className='chip chip-on';
+ el.className='chip chip-on';
  log('channel: '+ch)
 }
 function log(m){document.getElementById('log').innerText+=m+'\n'}
@@ -47,18 +45,23 @@ function checkUpdate(){
  fetch(BASE+'/version.txt?t='+Date.now(),{cache:'no-store'})
  .then(r=>{if(!r.ok)throw Error('HTTP '+r.status);return r.text()})
  .then(function(t){t=t.trim();log('remote: '+t);
-  var parts=t.indexOf('|')>0?t.split('|'):[t];var remoteVer=parts[0];dlUrl=parts[1]||'';
+  var parts=t.split('|');var remoteVer=parts[0];dlUrl=parts[1]||'';dlSha=parts[2]||'';
   if(!dlUrl)dlUrl=BASE+'/h5/index-v'+remoteVer.replace('0.1.0-dav-android-','')+'.html';
-  var local='0.1.0-dav-android-6';
-  if(remoteVer!==local){dlVer=remoteVer;
+  if(remoteVer!=='0.1.0-dav-android-6'){dlVer=remoteVer;
    log('*** NEW VERSION ***');document.getElementById('btnApply').disabled=false}
   else log('up to date')})
  .catch(function(e){log('ERR: '+e.message)})
 }
 function applyUpdate(){
  fetch(dlUrl+'?t='+Date.now(),{cache:'no-store'})
- .then(r=>{if(!r.ok)throw Error('HTTP '+r.status);return r.text()})
- .then(function(t){Android.saveCache(t);log('OK! restart app to apply')})
+ .then(r=>{if(!r.ok)throw Error('HTTP '+r.status);return r.arrayBuffer()})
+ .then(function(buf){
+  return crypto.subtle.digest('SHA-256',buf).then(function(hash){
+   var hex=Array.from(new Uint8Array(hash)).map(function(b){return b.toString(16).padStart(2,'0')}).join('');
+   if(dlSha&&hex!==dlSha){log('SHA256 MISMATCH!');return}
+   Android.saveCache(new TextDecoder().decode(buf));log('OK! restart app to apply')
+  })
+ })
  .catch(function(e){log('ERR: '+e.message)})
 }
 </script></body></html>
diff --git a/ota/version.txt b/ota/version.txt
index 4bdb7f5..0f70999 100644
--- a/ota/version.txt
+++ b/ota/version.txt
@@ -1 +1 @@
-0.1.0-dav-android-6|https://git.childish-ghost.com/LukeMackin/Yuzu-GCA/raw/branch/main/ota/h5/index-v6.html
\ No newline at end of file
+0.1.0-dav-android-6|https://git.childish-ghost.com/LukeMackin/Yuzu-GCA/raw/branch/main/ota/h5/index-v6.html|79a254cfce0a44a33cc0e56a5beb167d68fc30205d5055c7be6e21f96753dff2
\ No newline at end of file
diff --git a/packages/client-android/android/app/src/main/assets/index.html b/packages/client-android/android/app/src/main/assets/index.html
index 552d156..47c03ba 100644
--- a/packages/client-android/android/app/src/main/assets/index.html
+++ b/packages/client-android/android/app/src/main/assets/index.html
@@ -15,7 +15,7 @@ h1{font-size:18px;color:#38bdf8}
 <button class="btn btn-download" onclick="applyUpdate()" id="btnApply" disabled>下载更新</button>
 <div class="log" id="log"></div>
 <script>
-var dlUrl='',dlVer='';
+var dlUrl='',dlVer='',dlSha='';
 var BASE='https://git.childish-ghost.com/LukeMackin/Yuzu-GCA/raw/branch/main/ota';
 
 function log(m){document.getElementById('log').innerText+=m+'\n'}
@@ -24,7 +24,7 @@ function checkUpdate(){
  fetch(BASE+'/version.txt?t='+Date.now(),{cache:'no-store'})
  .then(r=>{if(!r.ok)throw Error('HTTP '+r.status);return r.text()})
  .then(function(t){t=t.trim();log('remote: '+t);
-  var parts=t.indexOf('|')>0?t.split('|'):[t];var remoteVer=parts[0];dlUrl=parts[1]||'';
+  var parts=t.split('|');var remoteVer=parts[0];dlUrl=parts[1]||'';dlSha=parts[2]||'';
   if(!dlUrl)dlUrl=BASE+'/h5/index-v'+remoteVer.replace('0.1.0-dav-android-','')+'.html';
   var local=document.getElementById('ver').innerText;
   if(remoteVer!==local&&remoteVer!=='v'+local&&'v'+remoteVer!==local){
@@ -35,8 +35,15 @@ function checkUpdate(){
 function applyUpdate(){
  log('downloading: '+dlUrl+' ...');
  fetch(dlUrl+'?t='+Date.now(),{cache:'no-store'})
- .then(r=>{if(!r.ok)throw Error('HTTP '+r.status);return r.text()})
- .then(function(t){Android.saveCache(t);log('OK! restart app to apply')})
+ .then(r=>{if(!r.ok)throw Error('HTTP '+r.status);return r.arrayBuffer()})
+ .then(function(buf){
+  return crypto.subtle.digest('SHA-256',buf).then(function(hash){
+   var hex=Array.from(new Uint8Array(hash)).map(function(b){return b.toString(16).padStart(2,'0')}).join('');
+   if(dlSha&&hex!==dlSha){log('SHA256 MISMATCH! expected:'+dlSha.slice(0,16)+'... got:'+hex.slice(0,16)+'...');return}
+   var text=new TextDecoder().decode(buf);
+   Android.saveCache(text);log('OK! restart app to apply')
+  })
+ })
  .catch(function(e){log('ERR: '+e.message)})
 }
 </script></body></html>
diff --git a/packages/client-android/android/app/src/main/java/dev/yuzu/gca/MainActivity.kt b/packages/client-android/android/app/src/main/java/dev/yuzu/gca/MainActivity.kt
index 8ed49d7..c17a755 100644
--- a/packages/client-android/android/app/src/main/java/dev/yuzu/gca/MainActivity.kt
+++ b/packages/client-android/android/app/src/main/java/dev/yuzu/gca/MainActivity.kt
@@ -14,13 +14,12 @@ class MainActivity : AppCompatActivity() {
         super.onCreate(savedInstanceState)
 
         val wv = WebView(this).apply {
-            WebView.setWebContentsDebuggingEnabled(true)
+            if (BuildConfig.DEBUG) {
+                WebView.setWebContentsDebuggingEnabled(true)
+            }
             settings.javaScriptEnabled = true
             settings.domStorageEnabled = true
             settings.allowFileAccess = true
-            settings.allowFileAccessFromFileURLs = true
-            settings.allowUniversalAccessFromFileURLs = true
-            settings.mixedContentMode = android.webkit.WebSettings.MIXED_CONTENT_ALWAYS_ALLOW
             addJavascriptInterface(Bridge(this@MainActivity), "Android")
 
             if (cacheFile.exists()) {