diff --git a/Tethering/src/com/android/networkstack/tethering/EntitlementManager.java b/Tethering/src/com/android/networkstack/tethering/EntitlementManager.java
index cd57c8d..fb16226 100644
--- a/Tethering/src/com/android/networkstack/tethering/EntitlementManager.java
+++ b/Tethering/src/com/android/networkstack/tethering/EntitlementManager.java
@@ -167,6 +167,11 @@
                 } else {
                     mLog.e("Current user (" + currentUserId
                             + ") is not allowed to perform entitlement check.");
+                    // If the user is not allowed to perform an entitlement check
+                    // (e.g., a non-admin user), notify the receiver immediately.
+                    // This is necessary because the entitlement check app cannot
+                    // be launched to conduct the check and deliver the results.
+                    receiver.send(TETHER_ERROR_PROVISIONING_FAILED, null);
                     return null;
                 }
             } else {
diff --git a/Tethering/tests/unit/src/com/android/networkstack/tethering/EntitlementManagerTest.java b/Tethering/tests/unit/src/com/android/networkstack/tethering/EntitlementManagerTest.java
index 8626b18..51c2d56 100644
--- a/Tethering/tests/unit/src/com/android/networkstack/tethering/EntitlementManagerTest.java
+++ b/Tethering/tests/unit/src/com/android/networkstack/tethering/EntitlementManagerTest.java
@@ -84,6 +84,7 @@
 
 import com.android.internal.util.test.BroadcastInterceptingContext;
 import com.android.modules.utils.build.SdkLevel;
+import com.android.net.module.util.ArrayTrackRecord;
 import com.android.net.module.util.SharedLog;
 import com.android.testutils.DevSdkIgnoreRule;
 
@@ -187,8 +188,9 @@
             if (intent != null) {
                 assertUiTetherProvisioningIntent(type, config, receiver, intent);
                 uiProvisionCount++;
+                // If the intent is null, the result is sent by the underlying method.
+                receiver.send(fakeEntitlementResult, null);
             }
-            receiver.send(fakeEntitlementResult, null);
             return intent;
         }
 
@@ -348,99 +350,43 @@
     public void testRequestLastEntitlementCacheValue() throws Exception {
         // 1. Entitlement check is not required.
         mDeps.fakeEntitlementResult = TETHER_ERROR_NO_ERROR;
-        ResultReceiver receiver = new ResultReceiver(null) {
-            @Override
-            protected void onReceiveResult(int resultCode, Bundle resultData) {
-                assertEquals(TETHER_ERROR_NO_ERROR, resultCode);
-            }
-        };
-        mEnMgr.requestLatestTetheringEntitlementResult(TETHERING_WIFI, receiver, true);
-        mLooper.dispatchAll();
+        assertLatestEntitlementResult(TETHERING_WIFI, TETHER_ERROR_NO_ERROR, true);
         assertEquals(0, mDeps.uiProvisionCount);
         mDeps.reset();
 
         setupForRequiredProvisioning();
         // 2. No cache value and don't need to run entitlement check.
-        receiver = new ResultReceiver(null) {
-            @Override
-            protected void onReceiveResult(int resultCode, Bundle resultData) {
-                assertEquals(TETHER_ERROR_ENTITLEMENT_UNKNOWN, resultCode);
-            }
-        };
-        mEnMgr.requestLatestTetheringEntitlementResult(TETHERING_WIFI, receiver, false);
-        mLooper.dispatchAll();
+        assertLatestEntitlementResult(TETHERING_WIFI, TETHER_ERROR_ENTITLEMENT_UNKNOWN, false);
         assertEquals(0, mDeps.uiProvisionCount);
         mDeps.reset();
         // 3. No cache value and ui entitlement check is needed.
         mDeps.fakeEntitlementResult = TETHER_ERROR_PROVISIONING_FAILED;
-        receiver = new ResultReceiver(null) {
-            @Override
-            protected void onReceiveResult(int resultCode, Bundle resultData) {
-                assertEquals(TETHER_ERROR_PROVISIONING_FAILED, resultCode);
-            }
-        };
-        mEnMgr.requestLatestTetheringEntitlementResult(TETHERING_WIFI, receiver, true);
-        mLooper.dispatchAll();
+        assertLatestEntitlementResult(TETHERING_WIFI, TETHER_ERROR_PROVISIONING_FAILED, true);
         assertEquals(1, mDeps.uiProvisionCount);
         mDeps.reset();
         // 4. Cache value is TETHER_ERROR_PROVISIONING_FAILED and don't need to run entitlement
         // check.
         mDeps.fakeEntitlementResult = TETHER_ERROR_NO_ERROR;
-        receiver = new ResultReceiver(null) {
-            @Override
-            protected void onReceiveResult(int resultCode, Bundle resultData) {
-                assertEquals(TETHER_ERROR_PROVISIONING_FAILED, resultCode);
-            }
-        };
-        mEnMgr.requestLatestTetheringEntitlementResult(TETHERING_WIFI, receiver, false);
-        mLooper.dispatchAll();
+        assertLatestEntitlementResult(TETHERING_WIFI, TETHER_ERROR_PROVISIONING_FAILED, false);
         assertEquals(0, mDeps.uiProvisionCount);
         mDeps.reset();
         // 5. Cache value is TETHER_ERROR_PROVISIONING_FAILED and ui entitlement check is needed.
         mDeps.fakeEntitlementResult = TETHER_ERROR_NO_ERROR;
-        receiver = new ResultReceiver(null) {
-            @Override
-            protected void onReceiveResult(int resultCode, Bundle resultData) {
-                assertEquals(TETHER_ERROR_NO_ERROR, resultCode);
-            }
-        };
-        mEnMgr.requestLatestTetheringEntitlementResult(TETHERING_WIFI, receiver, true);
-        mLooper.dispatchAll();
+        assertLatestEntitlementResult(TETHERING_WIFI, TETHER_ERROR_NO_ERROR, true);
         assertEquals(1, mDeps.uiProvisionCount);
         mDeps.reset();
         // 6. Cache value is TETHER_ERROR_NO_ERROR.
         mDeps.fakeEntitlementResult = TETHER_ERROR_NO_ERROR;
-        receiver = new ResultReceiver(null) {
-            @Override
-            protected void onReceiveResult(int resultCode, Bundle resultData) {
-                assertEquals(TETHER_ERROR_NO_ERROR, resultCode);
-            }
-        };
-        mEnMgr.requestLatestTetheringEntitlementResult(TETHERING_WIFI, receiver, true);
-        mLooper.dispatchAll();
+        assertLatestEntitlementResult(TETHERING_WIFI, TETHER_ERROR_NO_ERROR, true);
         assertEquals(0, mDeps.uiProvisionCount);
         mDeps.reset();
         // 7. Test get value for other downstream type.
-        receiver = new ResultReceiver(null) {
-            @Override
-            protected void onReceiveResult(int resultCode, Bundle resultData) {
-                assertEquals(TETHER_ERROR_ENTITLEMENT_UNKNOWN, resultCode);
-            }
-        };
-        mEnMgr.requestLatestTetheringEntitlementResult(TETHERING_USB, receiver, false);
-        mLooper.dispatchAll();
+        assertLatestEntitlementResult(TETHERING_USB, TETHER_ERROR_ENTITLEMENT_UNKNOWN, false);
         assertEquals(0, mDeps.uiProvisionCount);
         mDeps.reset();
         // 8. Test get value for invalid downstream type.
         mDeps.fakeEntitlementResult = TETHER_ERROR_NO_ERROR;
-        receiver = new ResultReceiver(null) {
-            @Override
-            protected void onReceiveResult(int resultCode, Bundle resultData) {
-                assertEquals(TETHER_ERROR_ENTITLEMENT_UNKNOWN, resultCode);
-            }
-        };
-        mEnMgr.requestLatestTetheringEntitlementResult(TETHERING_WIFI_P2P, receiver, true);
-        mLooper.dispatchAll();
+        assertLatestEntitlementResult(TETHERING_WIFI_P2P, TETHER_ERROR_ENTITLEMENT_UNKNOWN, true);
         assertEquals(0, mDeps.uiProvisionCount);
         mDeps.reset();
     }
@@ -660,6 +606,34 @@
         doTestUiProvisioningMultiUser(false, 1);
     }
 
+    private static class TestableResultReceiver extends ResultReceiver {
+        private static final long DEFAULT_TIMEOUT_MS = 200L;
+        private final ArrayTrackRecord<Integer>.ReadHead mHistory =
+                new ArrayTrackRecord<Integer>().newReadHead();
+
+        TestableResultReceiver(Handler handler) {
+            super(handler);
+        }
+
+        @Override
+        protected void onReceiveResult(int resultCode, Bundle resultData) {
+            mHistory.add(resultCode);
+        }
+
+        void expectResult(int resultCode) {
+            final int event = mHistory.poll(DEFAULT_TIMEOUT_MS, it -> true);
+            assertEquals(resultCode, event);
+        }
+    }
+
+    void assertLatestEntitlementResult(int downstreamType, int expectedCode,
+            boolean showEntitlementUi) {
+        final TestableResultReceiver receiver = new TestableResultReceiver(null);
+        mEnMgr.requestLatestTetheringEntitlementResult(downstreamType, receiver, showEntitlementUi);
+        mLooper.dispatchAll();
+        receiver.expectResult(expectedCode);
+    }
+
     private void doTestUiProvisioningMultiUser(boolean isAdminUser, int expectedUiProvisionCount) {
         setupForRequiredProvisioning();
         doReturn(isAdminUser).when(mUserManager).isAdminUser();
@@ -671,10 +645,19 @@
         mEnMgr.startProvisioningIfNeeded(TETHERING_USB, true);
         mLooper.dispatchAll();
         assertEquals(expectedUiProvisionCount, mDeps.uiProvisionCount);
+        if (expectedUiProvisionCount == 0) { // Failed to launch entitlement UI.
+            assertLatestEntitlementResult(TETHERING_USB, TETHER_ERROR_PROVISIONING_FAILED, false);
+            verify(mTetherProvisioningFailedListener).onTetherProvisioningFailed(TETHERING_USB,
+                    FAILED_TETHERING_REASON);
+        } else {
+            assertLatestEntitlementResult(TETHERING_USB, TETHER_ERROR_NO_ERROR, false);
+            verify(mTetherProvisioningFailedListener, never()).onTetherProvisioningFailed(anyInt(),
+                    anyString());
+        }
     }
 
     @Test
-    public void testsetExemptedDownstreamType() throws Exception {
+    public void testSetExemptedDownstreamType() {
         setupForRequiredProvisioning();
         // Cellular upstream is not permitted when no entitlement result.
         assertFalse(mEnMgr.isCellularUpstreamPermitted());
@@ -737,14 +720,7 @@
         setupCarrierConfig(false);
         setupForRequiredProvisioning();
         mDeps.fakeEntitlementResult = TETHER_ERROR_NO_ERROR;
-        ResultReceiver receiver = new ResultReceiver(null) {
-            @Override
-            protected void onReceiveResult(int resultCode, Bundle resultData) {
-                assertEquals(TETHER_ERROR_PROVISIONING_FAILED, resultCode);
-            }
-        };
-        mEnMgr.requestLatestTetheringEntitlementResult(TETHERING_WIFI, receiver, false);
-        mLooper.dispatchAll();
+        assertLatestEntitlementResult(TETHERING_WIFI, TETHER_ERROR_PROVISIONING_FAILED, false);
         assertEquals(0, mDeps.uiProvisionCount);
         mDeps.reset();
     }
diff --git a/framework/Android.bp b/framework/Android.bp
index a5a7d61..a93a532 100644
--- a/framework/Android.bp
+++ b/framework/Android.bp
@@ -158,6 +158,7 @@
 java_defaults {
     name: "CronetJavaDefaults",
     srcs: [":httpclient_api_sources"],
+    static_libs: ["com.android.net.http.flags-aconfig-java"],
     libs: [
         "androidx.annotation_annotation",
     ],
@@ -218,6 +219,7 @@
     },
     aconfig_declarations: [
         "com.android.net.flags-aconfig",
+        "com.android.net.http.flags-aconfig",
         "com.android.networksecurity.flags-aconfig",
     ],
 }
diff --git a/framework/api/module-lib-current.txt b/framework/api/module-lib-current.txt
index cd7307f..0129e5c 100644
--- a/framework/api/module-lib-current.txt
+++ b/framework/api/module-lib-current.txt
@@ -247,3 +247,11 @@
 
 }
 
+package android.net.http {
+
+  public abstract class HttpEngine {
+    method @FlaggedApi("android.net.http.preload_httpengine_in_zygote") public static void preload();
+  }
+
+}
+
diff --git a/networksecurity/service/src/com/android/server/net/ct/CertificateTransparencyDownloader.java b/networksecurity/service/src/com/android/server/net/ct/CertificateTransparencyDownloader.java
index d53f007..56a5ee5 100644
--- a/networksecurity/service/src/com/android/server/net/ct/CertificateTransparencyDownloader.java
+++ b/networksecurity/service/src/com/android/server/net/ct/CertificateTransparencyDownloader.java
@@ -15,11 +15,11 @@
  */
 package com.android.server.net.ct;
 
-import android.annotation.NonNull;
+import static java.nio.charset.StandardCharsets.UTF_8;
+
 import android.annotation.RequiresApi;
 import android.app.DownloadManager;
 import android.content.BroadcastReceiver;
-import android.content.ContentResolver;
 import android.content.Context;
 import android.content.Intent;
 import android.content.IntentFilter;
@@ -31,16 +31,12 @@
 
 import com.android.server.net.ct.DownloadHelper.DownloadStatus;
 
+import org.json.JSONException;
+import org.json.JSONObject;
+
 import java.io.IOException;
 import java.io.InputStream;
 import java.security.GeneralSecurityException;
-import java.security.InvalidKeyException;
-import java.security.KeyFactory;
-import java.security.PublicKey;
-import java.security.Signature;
-import java.security.spec.X509EncodedKeySpec;
-import java.util.Base64;
-import java.util.Optional;
 
 /** Helper class to download certificate transparency log files. */
 @RequiresApi(Build.VERSION_CODES.VANILLA_ICE_CREAM)
@@ -51,30 +47,22 @@
     private final Context mContext;
     private final DataStore mDataStore;
     private final DownloadHelper mDownloadHelper;
+    private final SignatureVerifier mSignatureVerifier;
     private final CertificateTransparencyInstaller mInstaller;
 
-    @NonNull private Optional<PublicKey> mPublicKey = Optional.empty();
-
-    @VisibleForTesting
     CertificateTransparencyDownloader(
             Context context,
             DataStore dataStore,
             DownloadHelper downloadHelper,
+            SignatureVerifier signatureVerifier,
             CertificateTransparencyInstaller installer) {
         mContext = context;
+        mSignatureVerifier = signatureVerifier;
         mDataStore = dataStore;
         mDownloadHelper = downloadHelper;
         mInstaller = installer;
     }
 
-    CertificateTransparencyDownloader(Context context, DataStore dataStore) {
-        this(
-                context,
-                dataStore,
-                new DownloadHelper(context),
-                new CertificateTransparencyInstaller());
-    }
-
     void initialize() {
         mInstaller.addCompatibilityVersion(Config.COMPATIBILITY_VERSION);
 
@@ -87,43 +75,31 @@
         }
     }
 
-    void setPublicKey(String publicKey) throws GeneralSecurityException {
-        try {
-            mPublicKey =
-                    Optional.of(
-                            KeyFactory.getInstance("RSA")
-                                    .generatePublic(
-                                            new X509EncodedKeySpec(
-                                                    Base64.getDecoder().decode(publicKey))));
-        } catch (IllegalArgumentException e) {
-            Log.e(TAG, "Invalid public key Base64 encoding", e);
-            mPublicKey = Optional.empty();
+    long startPublicKeyDownload() {
+        long downloadId = download(mDataStore.getProperty(Config.PUBLIC_KEY_URL));
+        if (downloadId != -1) {
+            mDataStore.setPropertyLong(Config.PUBLIC_KEY_DOWNLOAD_ID, downloadId);
+            mDataStore.store();
         }
+        return downloadId;
     }
 
-    @VisibleForTesting
-    void resetPublicKey() {
-        mPublicKey = Optional.empty();
+    long startMetadataDownload() {
+        long downloadId = download(mDataStore.getProperty(Config.METADATA_URL));
+        if (downloadId != -1) {
+            mDataStore.setPropertyLong(Config.METADATA_DOWNLOAD_ID, downloadId);
+            mDataStore.store();
+        }
+        return downloadId;
     }
 
-    void startMetadataDownload(String metadataUrl) {
-        long downloadId = download(metadataUrl);
-        if (downloadId == -1) {
-            Log.e(TAG, "Metadata download request failed for " + metadataUrl);
-            return;
+    long startContentDownload() {
+        long downloadId = download(mDataStore.getProperty(Config.CONTENT_URL));
+        if (downloadId != -1) {
+            mDataStore.setPropertyLong(Config.CONTENT_DOWNLOAD_ID, downloadId);
+            mDataStore.store();
         }
-        mDataStore.setPropertyLong(Config.METADATA_URL_KEY, downloadId);
-        mDataStore.store();
-    }
-
-    void startContentDownload(String contentUrl) {
-        long downloadId = download(contentUrl);
-        if (downloadId == -1) {
-            Log.e(TAG, "Content download request failed for " + contentUrl);
-            return;
-        }
-        mDataStore.setPropertyLong(Config.CONTENT_URL_KEY, downloadId);
-        mDataStore.store();
+        return downloadId;
     }
 
     @Override
@@ -140,6 +116,11 @@
             return;
         }
 
+        if (isPublicKeyDownloadId(completedId)) {
+            handlePublicKeyDownloadCompleted(completedId);
+            return;
+        }
+
         if (isMetadataDownloadId(completedId)) {
             handleMetadataDownloadCompleted(completedId);
             return;
@@ -150,7 +131,34 @@
             return;
         }
 
-        Log.e(TAG, "Download id " + completedId + " is neither metadata nor content.");
+        Log.i(TAG, "Download id " + completedId + " is not recognized.");
+    }
+
+    private void handlePublicKeyDownloadCompleted(long downloadId) {
+        DownloadStatus status = mDownloadHelper.getDownloadStatus(downloadId);
+        if (!status.isSuccessful()) {
+            handleDownloadFailed(status);
+            return;
+        }
+
+        Uri publicKeyUri = getPublicKeyDownloadUri();
+        if (publicKeyUri == null) {
+            Log.e(TAG, "Invalid public key URI");
+            return;
+        }
+
+        try {
+            mSignatureVerifier.setPublicKeyFrom(publicKeyUri);
+        } catch (GeneralSecurityException | IOException | IllegalArgumentException e) {
+            Log.e(TAG, "Error setting the public Key", e);
+            return;
+        }
+
+        if (startMetadataDownload() == -1) {
+            Log.e(TAG, "Metadata download not started.");
+        } else if (Config.DEBUG) {
+            Log.d(TAG, "Metadata download started successfully.");
+        }
     }
 
     private void handleMetadataDownloadCompleted(long downloadId) {
@@ -159,7 +167,11 @@
             handleDownloadFailed(status);
             return;
         }
-        startContentDownload(mDataStore.getProperty(Config.CONTENT_URL_PENDING));
+        if (startContentDownload() == -1) {
+            Log.e(TAG, "Content download not started.");
+        } else if (Config.DEBUG) {
+            Log.d(TAG, "Content download started successfully.");
+        }
     }
 
     private void handleContentDownloadCompleted(long downloadId) {
@@ -178,7 +190,7 @@
 
         boolean success = false;
         try {
-            success = verify(contentUri, metadataUri);
+            success = mSignatureVerifier.verify(contentUri, metadataUri);
         } catch (IOException | GeneralSecurityException e) {
             Log.e(TAG, "Could not verify new log list", e);
         }
@@ -187,11 +199,16 @@
             return;
         }
 
-        // TODO: validate file content.
+        String version = null;
+        try (InputStream inputStream = mContext.getContentResolver().openInputStream(contentUri)) {
+            version =
+                    new JSONObject(new String(inputStream.readAllBytes(), UTF_8))
+                            .getString("version");
+        } catch (JSONException | IOException e) {
+            Log.e(TAG, "Could not extract version from log list", e);
+            return;
+        }
 
-        String version = mDataStore.getProperty(Config.VERSION_PENDING);
-        String contentUrl = mDataStore.getProperty(Config.CONTENT_URL_PENDING);
-        String metadataUrl = mDataStore.getProperty(Config.METADATA_URL_PENDING);
         try (InputStream inputStream = mContext.getContentResolver().openInputStream(contentUri)) {
             success = mInstaller.install(Config.COMPATIBILITY_VERSION, inputStream, version);
         } catch (IOException e) {
@@ -202,32 +219,15 @@
         if (success) {
             // Update information about the stored version on successful install.
             mDataStore.setProperty(Config.VERSION, version);
-            mDataStore.setProperty(Config.CONTENT_URL, contentUrl);
-            mDataStore.setProperty(Config.METADATA_URL, metadataUrl);
             mDataStore.store();
         }
     }
 
     private void handleDownloadFailed(DownloadStatus status) {
-        Log.e(TAG, "Content download failed with " + status);
+        Log.e(TAG, "Download failed with " + status);
         // TODO(378626065): Report failure via statsd.
     }
 
-    private boolean verify(Uri file, Uri signature) throws IOException, GeneralSecurityException {
-        if (!mPublicKey.isPresent()) {
-            throw new InvalidKeyException("Missing public key for signature verification");
-        }
-        Signature verifier = Signature.getInstance("SHA256withRSA");
-        verifier.initVerify(mPublicKey.get());
-        ContentResolver contentResolver = mContext.getContentResolver();
-
-        try (InputStream fileStream = contentResolver.openInputStream(file);
-                InputStream signatureStream = contentResolver.openInputStream(signature)) {
-            verifier.update(fileStream.readAllBytes());
-            return verifier.verify(signatureStream.readAllBytes());
-        }
-    }
-
     private long download(String url) {
         try {
             return mDownloadHelper.startDownload(url);
@@ -238,20 +238,59 @@
     }
 
     @VisibleForTesting
+    long getPublicKeyDownloadId() {
+        return mDataStore.getPropertyLong(Config.PUBLIC_KEY_DOWNLOAD_ID, -1);
+    }
+
+    @VisibleForTesting
+    long getMetadataDownloadId() {
+        return mDataStore.getPropertyLong(Config.METADATA_DOWNLOAD_ID, -1);
+    }
+
+    @VisibleForTesting
+    long getContentDownloadId() {
+        return mDataStore.getPropertyLong(Config.CONTENT_DOWNLOAD_ID, -1);
+    }
+
+    @VisibleForTesting
+    boolean hasPublicKeyDownloadId() {
+        return getPublicKeyDownloadId() != -1;
+    }
+
+    @VisibleForTesting
+    boolean hasMetadataDownloadId() {
+        return getMetadataDownloadId() != -1;
+    }
+
+    @VisibleForTesting
+    boolean hasContentDownloadId() {
+        return getContentDownloadId() != -1;
+    }
+
+    @VisibleForTesting
+    boolean isPublicKeyDownloadId(long downloadId) {
+        return getPublicKeyDownloadId() == downloadId;
+    }
+
+    @VisibleForTesting
     boolean isMetadataDownloadId(long downloadId) {
-        return mDataStore.getPropertyLong(Config.METADATA_URL_KEY, -1) == downloadId;
+        return getMetadataDownloadId() == downloadId;
     }
 
     @VisibleForTesting
     boolean isContentDownloadId(long downloadId) {
-        return mDataStore.getPropertyLong(Config.CONTENT_URL_KEY, -1) == downloadId;
+        return getContentDownloadId() == downloadId;
+    }
+
+    private Uri getPublicKeyDownloadUri() {
+        return mDownloadHelper.getUri(getPublicKeyDownloadId());
     }
 
     private Uri getMetadataDownloadUri() {
-        return mDownloadHelper.getUri(mDataStore.getPropertyLong(Config.METADATA_URL_KEY, -1));
+        return mDownloadHelper.getUri(getMetadataDownloadId());
     }
 
     private Uri getContentDownloadUri() {
-        return mDownloadHelper.getUri(mDataStore.getPropertyLong(Config.CONTENT_URL_KEY, -1));
+        return mDownloadHelper.getUri(getContentDownloadId());
     }
 }
diff --git a/networksecurity/service/src/com/android/server/net/ct/CertificateTransparencyFlagsListener.java b/networksecurity/service/src/com/android/server/net/ct/CertificateTransparencyFlagsListener.java
index 93a7064..3138ea7 100644
--- a/networksecurity/service/src/com/android/server/net/ct/CertificateTransparencyFlagsListener.java
+++ b/networksecurity/service/src/com/android/server/net/ct/CertificateTransparencyFlagsListener.java
@@ -32,12 +32,15 @@
     private static final String TAG = "CertificateTransparencyFlagsListener";
 
     private final DataStore mDataStore;
+    private final SignatureVerifier mSignatureVerifier;
     private final CertificateTransparencyDownloader mCertificateTransparencyDownloader;
 
     CertificateTransparencyFlagsListener(
             DataStore dataStore,
+            SignatureVerifier signatureVerifier,
             CertificateTransparencyDownloader certificateTransparencyDownloader) {
         mDataStore = dataStore;
+        mSignatureVerifier = signatureVerifier;
         mCertificateTransparencyDownloader = certificateTransparencyDownloader;
     }
 
@@ -104,19 +107,22 @@
         }
 
         try {
-            mCertificateTransparencyDownloader.setPublicKey(newPublicKey);
-        } catch (GeneralSecurityException e) {
+            mSignatureVerifier.setPublicKey(newPublicKey);
+        } catch (GeneralSecurityException | IllegalArgumentException e) {
             Log.e(TAG, "Error setting the public Key", e);
             return;
         }
 
         // TODO: handle the case where there is already a pending download.
 
-        mDataStore.setProperty(Config.VERSION_PENDING, newVersion);
-        mDataStore.setProperty(Config.CONTENT_URL_PENDING, newContentUrl);
-        mDataStore.setProperty(Config.METADATA_URL_PENDING, newMetadataUrl);
+        mDataStore.setProperty(Config.CONTENT_URL, newContentUrl);
+        mDataStore.setProperty(Config.METADATA_URL, newMetadataUrl);
         mDataStore.store();
 
-        mCertificateTransparencyDownloader.startMetadataDownload(newMetadataUrl);
+        if (mCertificateTransparencyDownloader.startMetadataDownload() == -1) {
+            Log.e(TAG, "Metadata download not started.");
+        } else if (Config.DEBUG) {
+            Log.d(TAG, "Metadata download started successfully.");
+        }
     }
 }
diff --git a/networksecurity/service/src/com/android/server/net/ct/CertificateTransparencyJob.java b/networksecurity/service/src/com/android/server/net/ct/CertificateTransparencyJob.java
index 6fbf0ba..bf23cb0 100644
--- a/networksecurity/service/src/com/android/server/net/ct/CertificateTransparencyJob.java
+++ b/networksecurity/service/src/com/android/server/net/ct/CertificateTransparencyJob.java
@@ -24,11 +24,8 @@
 import android.content.IntentFilter;
 import android.os.Build;
 import android.os.SystemClock;
-import android.provider.DeviceConfig;
 import android.util.Log;
 
-import java.util.HashMap;
-
 /** Implementation of the Certificate Transparency job */
 @RequiresApi(Build.VERSION_CODES.VANILLA_ICE_CREAM)
 public class CertificateTransparencyJob extends BroadcastReceiver {
@@ -40,18 +37,14 @@
     private final Context mContext;
     private final DataStore mDataStore;
     private final CertificateTransparencyDownloader mCertificateTransparencyDownloader;
-    // TODO(b/374692404): remove dependency to flags.
-    private final CertificateTransparencyFlagsListener mFlagsListener;
     private final AlarmManager mAlarmManager;
 
     /** Creates a new {@link CertificateTransparencyJob} object. */
     public CertificateTransparencyJob(
             Context context,
             DataStore dataStore,
-            CertificateTransparencyDownloader certificateTransparencyDownloader,
-            CertificateTransparencyFlagsListener flagsListener) {
+            CertificateTransparencyDownloader certificateTransparencyDownloader) {
         mContext = context;
-        mFlagsListener = flagsListener;
         mDataStore = dataStore;
         mCertificateTransparencyDownloader = certificateTransparencyDownloader;
         mAlarmManager = context.getSystemService(AlarmManager.class);
@@ -81,7 +74,19 @@
             Log.w(TAG, "Received unexpected broadcast with action " + intent);
             return;
         }
-        mFlagsListener.onPropertiesChanged(
-                new DeviceConfig.Properties(Config.NAMESPACE_NETWORK_SECURITY, new HashMap<>()));
+        if (Config.DEBUG) {
+            Log.d(TAG, "Starting CT daily job.");
+        }
+
+        mDataStore.setProperty(Config.CONTENT_URL, Config.URL_LOG_LIST);
+        mDataStore.setProperty(Config.METADATA_URL, Config.URL_SIGNATURE);
+        mDataStore.setProperty(Config.PUBLIC_KEY_URL, Config.URL_PUBLIC_KEY);
+        mDataStore.store();
+
+        if (mCertificateTransparencyDownloader.startPublicKeyDownload() == -1) {
+            Log.e(TAG, "Public key download not started.");
+        } else if (Config.DEBUG) {
+            Log.d(TAG, "Public key download started successfully.");
+        }
     }
 }
diff --git a/networksecurity/service/src/com/android/server/net/ct/CertificateTransparencyService.java b/networksecurity/service/src/com/android/server/net/ct/CertificateTransparencyService.java
index ac55e44..92b2b09 100644
--- a/networksecurity/service/src/com/android/server/net/ct/CertificateTransparencyService.java
+++ b/networksecurity/service/src/com/android/server/net/ct/CertificateTransparencyService.java
@@ -28,8 +28,6 @@
 @RequiresApi(Build.VERSION_CODES.VANILLA_ICE_CREAM)
 public class CertificateTransparencyService extends ICertificateTransparencyManager.Stub {
 
-    private final DataStore mDataStore;
-    private final CertificateTransparencyDownloader mCertificateTransparencyDownloader;
     private final CertificateTransparencyFlagsListener mFlagsListener;
     private final CertificateTransparencyJob mCertificateTransparencyJob;
 
@@ -44,15 +42,21 @@
 
     /** Creates a new {@link CertificateTransparencyService} object. */
     public CertificateTransparencyService(Context context) {
-        mDataStore = new DataStore(Config.PREFERENCES_FILE);
-        mCertificateTransparencyDownloader =
-                new CertificateTransparencyDownloader(context, mDataStore);
+        DataStore dataStore = new DataStore(Config.PREFERENCES_FILE);
+        DownloadHelper downloadHelper = new DownloadHelper(context);
+        SignatureVerifier signatureVerifier = new SignatureVerifier(context);
+        CertificateTransparencyDownloader downloader =
+                new CertificateTransparencyDownloader(
+                        context,
+                        dataStore,
+                        downloadHelper,
+                        signatureVerifier,
+                        new CertificateTransparencyInstaller());
+
         mFlagsListener =
-                new CertificateTransparencyFlagsListener(
-                        mDataStore, mCertificateTransparencyDownloader);
+                new CertificateTransparencyFlagsListener(dataStore, signatureVerifier, downloader);
         mCertificateTransparencyJob =
-                new CertificateTransparencyJob(
-                        context, mDataStore, mCertificateTransparencyDownloader, mFlagsListener);
+                new CertificateTransparencyJob(context, dataStore, downloader);
     }
 
     /**
diff --git a/networksecurity/service/src/com/android/server/net/ct/Config.java b/networksecurity/service/src/com/android/server/net/ct/Config.java
index 242f13a..70d8e42 100644
--- a/networksecurity/service/src/com/android/server/net/ct/Config.java
+++ b/networksecurity/service/src/com/android/server/net/ct/Config.java
@@ -47,12 +47,17 @@
     static final String FLAG_PUBLIC_KEY = FLAGS_PREFIX + "public_key";
 
     // properties
-    static final String VERSION_PENDING = "version_pending";
     static final String VERSION = "version";
-    static final String CONTENT_URL_PENDING = "content_url_pending";
     static final String CONTENT_URL = "content_url";
-    static final String CONTENT_URL_KEY = "content_url_key";
-    static final String METADATA_URL_PENDING = "metadata_url_pending";
+    static final String CONTENT_DOWNLOAD_ID = "content_download_id";
     static final String METADATA_URL = "metadata_url";
-    static final String METADATA_URL_KEY = "metadata_url_key";
+    static final String METADATA_DOWNLOAD_ID = "metadata_download_id";
+    static final String PUBLIC_KEY_URL = "public_key_url";
+    static final String PUBLIC_KEY_DOWNLOAD_ID = "public_key_download_id";
+
+    // URLs
+    static final String URL_PREFIX = "https://www.gstatic.com/android/certificate_transparency/";
+    static final String URL_LOG_LIST = URL_PREFIX + "log_list.json";
+    static final String URL_SIGNATURE = URL_PREFIX + "log_list.sig";
+    static final String URL_PUBLIC_KEY = URL_PREFIX + "log_list.pub";
 }
diff --git a/networksecurity/service/src/com/android/server/net/ct/SignatureVerifier.java b/networksecurity/service/src/com/android/server/net/ct/SignatureVerifier.java
new file mode 100644
index 0000000..0b775ca
--- /dev/null
+++ b/networksecurity/service/src/com/android/server/net/ct/SignatureVerifier.java
@@ -0,0 +1,91 @@
+/*
+ * Copyright (C) 2024 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.android.server.net.ct;
+
+import android.annotation.NonNull;
+import android.annotation.RequiresApi;
+import android.content.ContentResolver;
+import android.content.Context;
+import android.net.Uri;
+import android.os.Build;
+
+import androidx.annotation.VisibleForTesting;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.security.GeneralSecurityException;
+import java.security.InvalidKeyException;
+import java.security.KeyFactory;
+import java.security.PublicKey;
+import java.security.Signature;
+import java.security.spec.X509EncodedKeySpec;
+import java.util.Base64;
+import java.util.Optional;
+
+/** Verifier of the log list signature. */
+@RequiresApi(Build.VERSION_CODES.VANILLA_ICE_CREAM)
+public class SignatureVerifier {
+
+    private final Context mContext;
+
+    @NonNull private Optional<PublicKey> mPublicKey = Optional.empty();
+
+    public SignatureVerifier(Context context) {
+        mContext = context;
+    }
+
+    @VisibleForTesting
+    Optional<PublicKey> getPublicKey() {
+        return mPublicKey;
+    }
+
+    void resetPublicKey() {
+        mPublicKey = Optional.empty();
+    }
+
+    void setPublicKeyFrom(Uri file) throws GeneralSecurityException, IOException {
+        try (InputStream fileStream = mContext.getContentResolver().openInputStream(file)) {
+            setPublicKey(new String(fileStream.readAllBytes()));
+        }
+    }
+
+    void setPublicKey(String publicKey) throws GeneralSecurityException {
+        setPublicKey(
+                KeyFactory.getInstance("RSA")
+                        .generatePublic(
+                                new X509EncodedKeySpec(Base64.getDecoder().decode(publicKey))));
+    }
+
+    @VisibleForTesting
+    void setPublicKey(PublicKey publicKey) {
+        mPublicKey = Optional.of(publicKey);
+    }
+
+    boolean verify(Uri file, Uri signature) throws GeneralSecurityException, IOException {
+        if (!mPublicKey.isPresent()) {
+            throw new InvalidKeyException("Missing public key for signature verification");
+        }
+        Signature verifier = Signature.getInstance("SHA256withRSA");
+        verifier.initVerify(mPublicKey.get());
+        ContentResolver contentResolver = mContext.getContentResolver();
+
+        try (InputStream fileStream = contentResolver.openInputStream(file);
+                InputStream signatureStream = contentResolver.openInputStream(signature)) {
+            verifier.update(fileStream.readAllBytes());
+            return verifier.verify(signatureStream.readAllBytes());
+        }
+    }
+}
diff --git a/networksecurity/tests/unit/src/com/android/server/net/ct/CertificateTransparencyDownloaderTest.java b/networksecurity/tests/unit/src/com/android/server/net/ct/CertificateTransparencyDownloaderTest.java
index fb55295..ffa1283 100644
--- a/networksecurity/tests/unit/src/com/android/server/net/ct/CertificateTransparencyDownloaderTest.java
+++ b/networksecurity/tests/unit/src/com/android/server/net/ct/CertificateTransparencyDownloaderTest.java
@@ -18,21 +18,27 @@
 import static com.google.common.truth.Truth.assertThat;
 
 import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.ArgumentMatchers.anyString;
 import static org.mockito.ArgumentMatchers.eq;
 import static org.mockito.Mockito.never;
-import static org.mockito.Mockito.times;
 import static org.mockito.Mockito.verify;
 import static org.mockito.Mockito.when;
 
+import static java.nio.charset.StandardCharsets.UTF_8;
+
 import android.app.DownloadManager;
+import android.app.DownloadManager.Query;
+import android.app.DownloadManager.Request;
 import android.content.Context;
 import android.content.Intent;
+import android.database.Cursor;
+import android.database.MatrixCursor;
 import android.net.Uri;
 
 import androidx.test.platform.app.InstrumentationRegistry;
 
-import com.android.server.net.ct.DownloadHelper.DownloadStatus;
-
+import org.json.JSONException;
+import org.json.JSONObject;
 import org.junit.After;
 import org.junit.Before;
 import org.junit.Test;
@@ -59,7 +65,7 @@
 @RunWith(JUnit4.class)
 public class CertificateTransparencyDownloaderTest {
 
-    @Mock private DownloadHelper mDownloadHelper;
+    @Mock private DownloadManager mDownloadManager;
     @Mock private CertificateTransparencyInstaller mCertificateTransparencyInstaller;
 
     private PrivateKey mPrivateKey;
@@ -67,12 +73,14 @@
     private Context mContext;
     private File mTempFile;
     private DataStore mDataStore;
+    private SignatureVerifier mSignatureVerifier;
     private CertificateTransparencyDownloader mCertificateTransparencyDownloader;
 
+    private long mNextDownloadId = 666;
+
     @Before
     public void setUp() throws IOException, GeneralSecurityException {
         MockitoAnnotations.initMocks(this);
-
         KeyPairGenerator instance = KeyPairGenerator.getInstance("RSA");
         KeyPair keyPair = instance.generateKeyPair();
         mPrivateKey = keyPair.getPrivate();
@@ -81,195 +89,275 @@
         mContext = InstrumentationRegistry.getInstrumentation().getContext();
         mTempFile = File.createTempFile("datastore-test", ".properties");
         mDataStore = new DataStore(mTempFile);
-        mDataStore.load();
-
+        mSignatureVerifier = new SignatureVerifier(mContext);
         mCertificateTransparencyDownloader =
                 new CertificateTransparencyDownloader(
-                        mContext, mDataStore, mDownloadHelper, mCertificateTransparencyInstaller);
+                        mContext,
+                        mDataStore,
+                        new DownloadHelper(mDownloadManager),
+                        mSignatureVerifier,
+                        mCertificateTransparencyInstaller);
+
+        prepareDataStore();
+        prepareDownloadManager();
     }
 
     @After
     public void tearDown() {
         mTempFile.delete();
-        mCertificateTransparencyDownloader.resetPublicKey();
+        mSignatureVerifier.resetPublicKey();
+    }
+
+    @Test
+    public void testDownloader_startPublicKeyDownload() {
+        assertThat(mCertificateTransparencyDownloader.hasPublicKeyDownloadId()).isFalse();
+        long downloadId = mCertificateTransparencyDownloader.startPublicKeyDownload();
+
+        assertThat(mCertificateTransparencyDownloader.hasPublicKeyDownloadId()).isTrue();
+        assertThat(mCertificateTransparencyDownloader.isPublicKeyDownloadId(downloadId)).isTrue();
     }
 
     @Test
     public void testDownloader_startMetadataDownload() {
-        String metadataUrl = "http://test-metadata.org";
-        long downloadId = 666;
-        when(mDownloadHelper.startDownload(metadataUrl)).thenReturn(downloadId);
+        assertThat(mCertificateTransparencyDownloader.hasMetadataDownloadId()).isFalse();
+        long downloadId = mCertificateTransparencyDownloader.startMetadataDownload();
 
-        assertThat(mCertificateTransparencyDownloader.isMetadataDownloadId(downloadId)).isFalse();
-        mCertificateTransparencyDownloader.startMetadataDownload(metadataUrl);
+        assertThat(mCertificateTransparencyDownloader.hasMetadataDownloadId()).isTrue();
         assertThat(mCertificateTransparencyDownloader.isMetadataDownloadId(downloadId)).isTrue();
     }
 
     @Test
     public void testDownloader_startContentDownload() {
-        String contentUrl = "http://test-content.org";
-        long downloadId = 666;
-        when(mDownloadHelper.startDownload(contentUrl)).thenReturn(downloadId);
+        assertThat(mCertificateTransparencyDownloader.hasContentDownloadId()).isFalse();
+        long downloadId = mCertificateTransparencyDownloader.startContentDownload();
 
-        assertThat(mCertificateTransparencyDownloader.isContentDownloadId(downloadId)).isFalse();
-        mCertificateTransparencyDownloader.startContentDownload(contentUrl);
+        assertThat(mCertificateTransparencyDownloader.hasContentDownloadId()).isTrue();
         assertThat(mCertificateTransparencyDownloader.isContentDownloadId(downloadId)).isTrue();
     }
 
     @Test
-    public void testDownloader_metadataDownloadSuccess_startContentDownload() {
-        long metadataId = 123;
-        mDataStore.setPropertyLong(Config.METADATA_URL_KEY, metadataId);
-        when(mDownloadHelper.getDownloadStatus(metadataId))
-                .thenReturn(makeSuccessfulDownloadStatus(metadataId));
-        long contentId = 666;
-        String contentUrl = "http://test-content.org";
-        mDataStore.setProperty(Config.CONTENT_URL_PENDING, contentUrl);
-        when(mDownloadHelper.startDownload(contentUrl)).thenReturn(contentId);
+    public void testDownloader_publicKeyDownloadSuccess_updatePublicKey_startMetadataDownload()
+            throws Exception {
+        long publicKeyId = mCertificateTransparencyDownloader.startPublicKeyDownload();
+        setSuccessfulDownload(publicKeyId, writePublicKeyToFile(mPublicKey));
 
+        assertThat(mSignatureVerifier.getPublicKey()).isEmpty();
+        assertThat(mCertificateTransparencyDownloader.hasMetadataDownloadId()).isFalse();
+        mCertificateTransparencyDownloader.onReceive(
+                mContext, makeDownloadCompleteIntent(publicKeyId));
+
+        assertThat(mSignatureVerifier.getPublicKey()).hasValue(mPublicKey);
+        assertThat(mCertificateTransparencyDownloader.hasMetadataDownloadId()).isTrue();
+    }
+
+    @Test
+    public void
+            testDownloader_publicKeyDownloadSuccess_updatePublicKeyFail_doNotStartMetadataDownload()
+                    throws Exception {
+        long publicKeyId = mCertificateTransparencyDownloader.startPublicKeyDownload();
+        setSuccessfulDownload(
+                publicKeyId, writeToFile("i_am_not_a_base64_encoded_public_key".getBytes()));
+
+        assertThat(mSignatureVerifier.getPublicKey()).isEmpty();
+        assertThat(mCertificateTransparencyDownloader.hasMetadataDownloadId()).isFalse();
+        mCertificateTransparencyDownloader.onReceive(
+                mContext, makeDownloadCompleteIntent(publicKeyId));
+
+        assertThat(mSignatureVerifier.getPublicKey()).isEmpty();
+        assertThat(mCertificateTransparencyDownloader.hasMetadataDownloadId()).isFalse();
+    }
+
+    @Test
+    public void testDownloader_publicKeyDownloadFail_doNotUpdatePublicKey() throws Exception {
+        long publicKeyId = mCertificateTransparencyDownloader.startPublicKeyDownload();
+        setFailedDownload(
+                publicKeyId, // Failure cases where we give up on the download.
+                DownloadManager.ERROR_INSUFFICIENT_SPACE,
+                DownloadManager.ERROR_HTTP_DATA_ERROR);
+        Intent downloadCompleteIntent = makeDownloadCompleteIntent(publicKeyId);
+
+        assertThat(mSignatureVerifier.getPublicKey()).isEmpty();
+        assertThat(mCertificateTransparencyDownloader.hasMetadataDownloadId()).isFalse();
+        mCertificateTransparencyDownloader.onReceive(mContext, downloadCompleteIntent);
+        mCertificateTransparencyDownloader.onReceive(mContext, downloadCompleteIntent);
+
+        assertThat(mSignatureVerifier.getPublicKey()).isEmpty();
+        assertThat(mCertificateTransparencyDownloader.hasMetadataDownloadId()).isFalse();
+    }
+
+    @Test
+    public void testDownloader_metadataDownloadSuccess_startContentDownload() {
+        long metadataId = mCertificateTransparencyDownloader.startMetadataDownload();
+        setSuccessfulDownload(metadataId, new File("log_list.sig"));
+
+        assertThat(mCertificateTransparencyDownloader.hasContentDownloadId()).isFalse();
         mCertificateTransparencyDownloader.onReceive(
                 mContext, makeDownloadCompleteIntent(metadataId));
 
-        assertThat(mCertificateTransparencyDownloader.isContentDownloadId(contentId)).isTrue();
+        assertThat(mCertificateTransparencyDownloader.hasContentDownloadId()).isTrue();
     }
 
     @Test
     public void testDownloader_metadataDownloadFail_doNotStartContentDownload() {
-        long metadataId = 123;
-        mDataStore.setPropertyLong(Config.METADATA_URL_KEY, metadataId);
-        String contentUrl = "http://test-content.org";
-        mDataStore.setProperty(Config.CONTENT_URL_PENDING, contentUrl);
+        long metadataId = mCertificateTransparencyDownloader.startMetadataDownload();
+        setFailedDownload(
+                metadataId,
+                // Failure cases where we give up on the download.
+                DownloadManager.ERROR_INSUFFICIENT_SPACE,
+                DownloadManager.ERROR_HTTP_DATA_ERROR);
         Intent downloadCompleteIntent = makeDownloadCompleteIntent(metadataId);
-        // In all these failure cases we give up on the download.
-        when(mDownloadHelper.getDownloadStatus(metadataId))
-                .thenReturn(
-                        makeHttpErrorDownloadStatus(metadataId),
-                        makeStorageErrorDownloadStatus(metadataId));
 
+        assertThat(mCertificateTransparencyDownloader.hasContentDownloadId()).isFalse();
         mCertificateTransparencyDownloader.onReceive(mContext, downloadCompleteIntent);
         mCertificateTransparencyDownloader.onReceive(mContext, downloadCompleteIntent);
 
-        verify(mDownloadHelper, never()).startDownload(contentUrl);
+        assertThat(mCertificateTransparencyDownloader.hasContentDownloadId()).isFalse();
     }
 
     @Test
     public void testDownloader_contentDownloadSuccess_installSuccess_updateDataStore()
             throws Exception {
-        String version = "456";
-        long contentId = 666;
-        File logListFile = File.createTempFile("log_list", "json");
-        Uri contentUri = Uri.fromFile(logListFile);
-        long metadataId = 123;
+        String newVersion = "456";
+        File logListFile = makeLogListFile(newVersion);
         File metadataFile = sign(logListFile);
-        Uri metadataUri = Uri.fromFile(metadataFile);
-        mCertificateTransparencyDownloader.setPublicKey(
-                Base64.getEncoder().encodeToString(mPublicKey.getEncoded()));
-        setUpContentDownloadCompleteSuccessful(
-                version, metadataId, metadataUri, contentId, contentUri);
+        mSignatureVerifier.setPublicKey(mPublicKey);
+        long metadataId = mCertificateTransparencyDownloader.startMetadataDownload();
+        setSuccessfulDownload(metadataId, metadataFile);
+        long contentId = mCertificateTransparencyDownloader.startContentDownload();
+        setSuccessfulDownload(contentId, logListFile);
         when(mCertificateTransparencyInstaller.install(
-                        eq(Config.COMPATIBILITY_VERSION), any(), eq(version)))
+                        eq(Config.COMPATIBILITY_VERSION), any(), anyString()))
                 .thenReturn(true);
 
-        assertThat(mDataStore.getProperty(Config.VERSION)).isNull();
-        assertThat(mDataStore.getProperty(Config.CONTENT_URL)).isNull();
-        assertThat(mDataStore.getProperty(Config.METADATA_URL)).isNull();
+        assertNoVersionIsInstalled();
         mCertificateTransparencyDownloader.onReceive(
                 mContext, makeDownloadCompleteIntent(contentId));
 
-        verify(mCertificateTransparencyInstaller, times(1))
-                .install(eq(Config.COMPATIBILITY_VERSION), any(), eq(version));
-        assertThat(mDataStore.getProperty(Config.VERSION)).isEqualTo(version);
-        assertThat(mDataStore.getProperty(Config.CONTENT_URL)).isEqualTo(contentUri.toString());
-        assertThat(mDataStore.getProperty(Config.METADATA_URL)).isEqualTo(metadataUri.toString());
+        assertInstallSuccessful(newVersion);
     }
 
     @Test
     public void testDownloader_contentDownloadFail_doNotInstall() throws Exception {
-        mDataStore.setProperty(Config.VERSION_PENDING, "123");
-        long contentId = 666;
+        long contentId = mCertificateTransparencyDownloader.startContentDownload();
+        setFailedDownload(
+                contentId,
+                // Failure cases where we give up on the download.
+                DownloadManager.ERROR_INSUFFICIENT_SPACE,
+                DownloadManager.ERROR_HTTP_DATA_ERROR);
         Intent downloadCompleteIntent = makeDownloadCompleteIntent(contentId);
-        // In all these failure cases we give up on the download.
-        when(mDownloadHelper.getDownloadStatus(contentId))
-                .thenReturn(
-                        makeHttpErrorDownloadStatus(contentId),
-                        makeStorageErrorDownloadStatus(contentId));
 
         mCertificateTransparencyDownloader.onReceive(mContext, downloadCompleteIntent);
         mCertificateTransparencyDownloader.onReceive(mContext, downloadCompleteIntent);
-        mCertificateTransparencyDownloader.onReceive(mContext, downloadCompleteIntent);
 
         verify(mCertificateTransparencyInstaller, never()).install(any(), any(), any());
-        assertThat(mDataStore.getProperty(Config.VERSION)).isNull();
-        assertThat(mDataStore.getProperty(Config.CONTENT_URL)).isNull();
-        assertThat(mDataStore.getProperty(Config.METADATA_URL)).isNull();
+        assertNoVersionIsInstalled();
     }
 
     @Test
     public void testDownloader_contentDownloadSuccess_installFail_doNotUpdateDataStore()
             throws Exception {
-        String version = "456";
-        long contentId = 666;
-        File logListFile = File.createTempFile("log_list", "json");
-        Uri contentUri = Uri.fromFile(logListFile);
-        long metadataId = 123;
+        File logListFile = makeLogListFile("456");
         File metadataFile = sign(logListFile);
-        Uri metadataUri = Uri.fromFile(metadataFile);
-        setUpContentDownloadCompleteSuccessful(
-                version, metadataId, metadataUri, contentId, contentUri);
+        mSignatureVerifier.setPublicKey(mPublicKey);
+        long metadataId = mCertificateTransparencyDownloader.startMetadataDownload();
+        setSuccessfulDownload(metadataId, metadataFile);
+        long contentId = mCertificateTransparencyDownloader.startContentDownload();
+        setSuccessfulDownload(contentId, logListFile);
         when(mCertificateTransparencyInstaller.install(
-                        eq(Config.COMPATIBILITY_VERSION), any(), eq(version)))
+                        eq(Config.COMPATIBILITY_VERSION), any(), anyString()))
                 .thenReturn(false);
 
+        assertNoVersionIsInstalled();
         mCertificateTransparencyDownloader.onReceive(
                 mContext, makeDownloadCompleteIntent(contentId));
 
-        assertThat(mDataStore.getProperty(Config.VERSION)).isNull();
-        assertThat(mDataStore.getProperty(Config.CONTENT_URL)).isNull();
-        assertThat(mDataStore.getProperty(Config.METADATA_URL)).isNull();
+        assertNoVersionIsInstalled();
     }
 
     @Test
     public void testDownloader_contentDownloadSuccess_verificationFail_doNotInstall()
-            throws IOException {
-        String version = "456";
-        long contentId = 666;
-        Uri contentUri = Uri.fromFile(File.createTempFile("log_list", "json"));
-        long metadataId = 123;
-        Uri metadataUri = Uri.fromFile(File.createTempFile("log_list-wrong_metadata", "sig"));
-        setUpContentDownloadCompleteSuccessful(
-                version, metadataId, metadataUri, contentId, contentUri);
+            throws Exception {
+        File logListFile = makeLogListFile("456");
+        File metadataFile = File.createTempFile("log_list-wrong_metadata", "sig");
+        mSignatureVerifier.setPublicKey(mPublicKey);
+        long metadataId = mCertificateTransparencyDownloader.startMetadataDownload();
+        setSuccessfulDownload(metadataId, metadataFile);
+        long contentId = mCertificateTransparencyDownloader.startContentDownload();
+        setSuccessfulDownload(contentId, logListFile);
 
+        assertNoVersionIsInstalled();
         mCertificateTransparencyDownloader.onReceive(
                 mContext, makeDownloadCompleteIntent(contentId));
 
         verify(mCertificateTransparencyInstaller, never())
-                .install(eq(Config.COMPATIBILITY_VERSION), any(), eq(version));
-        assertThat(mDataStore.getProperty(Config.VERSION)).isNull();
-        assertThat(mDataStore.getProperty(Config.CONTENT_URL)).isNull();
-        assertThat(mDataStore.getProperty(Config.METADATA_URL)).isNull();
+                .install(eq(Config.COMPATIBILITY_VERSION), any(), anyString());
+        assertNoVersionIsInstalled();
     }
 
     @Test
     public void testDownloader_contentDownloadSuccess_missingVerificationPublicKey_doNotInstall()
             throws Exception {
-        String version = "456";
-        long contentId = 666;
-        File logListFile = File.createTempFile("log_list", "json");
-        Uri contentUri = Uri.fromFile(logListFile);
-        long metadataId = 123;
+        File logListFile = makeLogListFile("456");
         File metadataFile = sign(logListFile);
-        Uri metadataUri = Uri.fromFile(metadataFile);
-        setUpContentDownloadCompleteSuccessful(
-                version, metadataId, metadataUri, contentId, contentUri);
+        mSignatureVerifier.resetPublicKey();
+        long metadataId = mCertificateTransparencyDownloader.startMetadataDownload();
+        setSuccessfulDownload(metadataId, metadataFile);
+        long contentId = mCertificateTransparencyDownloader.startContentDownload();
+        setSuccessfulDownload(contentId, logListFile);
 
+        assertNoVersionIsInstalled();
         mCertificateTransparencyDownloader.onReceive(
                 mContext, makeDownloadCompleteIntent(contentId));
 
         verify(mCertificateTransparencyInstaller, never())
-                .install(eq(Config.COMPATIBILITY_VERSION), any(), eq(version));
+                .install(eq(Config.COMPATIBILITY_VERSION), any(), anyString());
+        assertNoVersionIsInstalled();
+    }
+
+    @Test
+    public void testDownloader_endToEndSuccess_installNewVersion() throws Exception {
+        String newVersion = "456";
+        File logListFile = makeLogListFile(newVersion);
+        File metadataFile = sign(logListFile);
+        File publicKeyFile = writePublicKeyToFile(mPublicKey);
+
+        assertNoVersionIsInstalled();
+
+        // 1. Start download of public key.
+        long publicKeyId = mCertificateTransparencyDownloader.startPublicKeyDownload();
+
+        // 2. On successful public key download, set the key and start the metatadata download.
+        setSuccessfulDownload(publicKeyId, publicKeyFile);
+
+        mCertificateTransparencyDownloader.onReceive(
+                mContext, makeDownloadCompleteIntent(publicKeyId));
+
+        // 3. On successful metadata download, start the content download.
+        long metadataId = mCertificateTransparencyDownloader.getMetadataDownloadId();
+        setSuccessfulDownload(metadataId, metadataFile);
+
+        mCertificateTransparencyDownloader.onReceive(
+                mContext, makeDownloadCompleteIntent(metadataId));
+
+        // 4. On successful content download, verify the signature and install the new version.
+        long contentId = mCertificateTransparencyDownloader.getContentDownloadId();
+        setSuccessfulDownload(contentId, logListFile);
+        when(mCertificateTransparencyInstaller.install(
+                        eq(Config.COMPATIBILITY_VERSION), any(), anyString()))
+                .thenReturn(true);
+
+        mCertificateTransparencyDownloader.onReceive(
+                mContext, makeDownloadCompleteIntent(contentId));
+
+        assertInstallSuccessful(newVersion);
+    }
+
+    private void assertNoVersionIsInstalled() {
         assertThat(mDataStore.getProperty(Config.VERSION)).isNull();
-        assertThat(mDataStore.getProperty(Config.CONTENT_URL)).isNull();
-        assertThat(mDataStore.getProperty(Config.METADATA_URL)).isNull();
+    }
+
+    private void assertInstallSuccessful(String version) {
+        assertThat(mDataStore.getProperty(Config.VERSION)).isEqualTo(version);
     }
 
     private Intent makeDownloadCompleteIntent(long downloadId) {
@@ -277,43 +365,76 @@
                 .putExtra(DownloadManager.EXTRA_DOWNLOAD_ID, downloadId);
     }
 
-    private void setUpContentDownloadCompleteSuccessful(
-            String version, long metadataId, Uri metadataUri, long contentId, Uri contentUri)
-            throws IOException {
-        mDataStore.setProperty(Config.VERSION_PENDING, version);
-
-        mDataStore.setPropertyLong(Config.METADATA_URL_KEY, metadataId);
-        mDataStore.setProperty(Config.METADATA_URL_PENDING, metadataUri.toString());
-        when(mDownloadHelper.getUri(metadataId)).thenReturn(metadataUri);
-
-        mDataStore.setPropertyLong(Config.CONTENT_URL_KEY, contentId);
-        mDataStore.setProperty(Config.CONTENT_URL_PENDING, contentUri.toString());
-        when(mDownloadHelper.getDownloadStatus(contentId))
-                .thenReturn(makeSuccessfulDownloadStatus(contentId));
-        when(mDownloadHelper.getUri(contentId)).thenReturn(contentUri);
+    private void prepareDataStore() {
+        mDataStore.load();
+        mDataStore.setProperty(Config.CONTENT_URL, Config.URL_LOG_LIST);
+        mDataStore.setProperty(Config.METADATA_URL, Config.URL_SIGNATURE);
+        mDataStore.setProperty(Config.PUBLIC_KEY_URL, Config.URL_PUBLIC_KEY);
     }
 
-    private DownloadStatus makeSuccessfulDownloadStatus(long downloadId) {
-        return DownloadStatus.builder()
-                .setDownloadId(downloadId)
-                .setStatus(DownloadManager.STATUS_SUCCESSFUL)
-                .build();
+    private void prepareDownloadManager() {
+        when(mDownloadManager.enqueue(any(Request.class)))
+                .thenAnswer(invocation -> mNextDownloadId++);
     }
 
-    private DownloadStatus makeStorageErrorDownloadStatus(long downloadId) {
-        return DownloadStatus.builder()
-                .setDownloadId(downloadId)
-                .setStatus(DownloadManager.STATUS_FAILED)
-                .setReason(DownloadManager.ERROR_INSUFFICIENT_SPACE)
-                .build();
+    private Cursor makeSuccessfulDownloadCursor() {
+        MatrixCursor cursor =
+                new MatrixCursor(
+                        new String[] {
+                            DownloadManager.COLUMN_STATUS, DownloadManager.COLUMN_REASON
+                        });
+        cursor.addRow(new Object[] {DownloadManager.STATUS_SUCCESSFUL, -1});
+        return cursor;
     }
 
-    private DownloadStatus makeHttpErrorDownloadStatus(long downloadId) {
-        return DownloadStatus.builder()
-                .setDownloadId(downloadId)
-                .setStatus(DownloadManager.STATUS_FAILED)
-                .setReason(DownloadManager.ERROR_HTTP_DATA_ERROR)
-                .build();
+    private void setSuccessfulDownload(long downloadId, File file) {
+        when(mDownloadManager.query(any(Query.class))).thenReturn(makeSuccessfulDownloadCursor());
+        when(mDownloadManager.getUriForDownloadedFile(downloadId)).thenReturn(Uri.fromFile(file));
+    }
+
+    private Cursor makeFailedDownloadCursor(int error) {
+        MatrixCursor cursor =
+                new MatrixCursor(
+                        new String[] {
+                            DownloadManager.COLUMN_STATUS, DownloadManager.COLUMN_REASON
+                        });
+        cursor.addRow(new Object[] {DownloadManager.STATUS_FAILED, error});
+        return cursor;
+    }
+
+    private void setFailedDownload(long downloadId, int... downloadManagerErrors) {
+        Cursor first = makeFailedDownloadCursor(downloadManagerErrors[0]);
+        Cursor[] others = new Cursor[downloadManagerErrors.length - 1];
+        for (int i = 1; i < downloadManagerErrors.length; i++) {
+            others[i - 1] = makeFailedDownloadCursor(downloadManagerErrors[i]);
+        }
+        when(mDownloadManager.query(any())).thenReturn(first, others);
+        when(mDownloadManager.getUriForDownloadedFile(downloadId)).thenReturn(null);
+    }
+
+    private File writePublicKeyToFile(PublicKey publicKey)
+            throws IOException, GeneralSecurityException {
+        return writeToFile(Base64.getEncoder().encode(publicKey.getEncoded()));
+    }
+
+    private File writeToFile(byte[] bytes) throws IOException, GeneralSecurityException {
+        File file = File.createTempFile("temp_file", "tmp");
+
+        try (OutputStream outputStream = new FileOutputStream(file)) {
+            outputStream.write(bytes);
+        }
+
+        return file;
+    }
+
+    private File makeLogListFile(String version) throws IOException, JSONException {
+        File logListFile = File.createTempFile("log_list", "json");
+
+        try (OutputStream outputStream = new FileOutputStream(logListFile)) {
+            outputStream.write(new JSONObject().put("version", version).toString().getBytes(UTF_8));
+        }
+
+        return logListFile;
     }
 
     private File sign(File file) throws IOException, GeneralSecurityException {
diff --git a/service-t/src/com/android/server/ethernet/EthernetTracker.java b/service-t/src/com/android/server/ethernet/EthernetTracker.java
index 07469b1..5228aab 100644
--- a/service-t/src/com/android/server/ethernet/EthernetTracker.java
+++ b/service-t/src/com/android/server/ethernet/EthernetTracker.java
@@ -139,8 +139,8 @@
     private int mTetheringInterfaceMode = INTERFACE_MODE_CLIENT;
     // Tracks whether clients were notified that the tethered interface is available
     private boolean mTetheredInterfaceWasAvailable = false;
-
-    private int mEthernetState = ETHERNET_STATE_ENABLED;
+    // Tracks the current state of ethernet as configured by EthernetManager#setEthernetEnabled.
+    private boolean mIsEthernetEnabled = true;
 
     private class TetheredInterfaceRequestList extends
             RemoteCallbackList<ITetheredInterfaceCallback> {
@@ -444,7 +444,7 @@
                 unicastInterfaceStateChange(listener, mTetheringInterface);
             }
 
-            unicastEthernetStateChange(listener, mEthernetState);
+            unicastEthernetStateChange(listener, mIsEthernetEnabled);
         });
     }
 
@@ -594,11 +594,11 @@
             // already running an UP event is created after adding the interface.
             config = NetdUtils.getInterfaceConfigParcel(mNetd, iface);
             // Only bring the interface up when ethernet is enabled.
-            if (mEthernetState == ETHERNET_STATE_ENABLED) {
+            if (mIsEthernetEnabled) {
                 // As a side-effect, NetdUtils#setInterfaceUp() also clears the interface's IPv4
                 // address and readds it which *could* lead to unexpected behavior in the future.
                 NetdUtils.setInterfaceUp(mNetd, iface);
-            } else if (mEthernetState == ETHERNET_STATE_DISABLED) {
+            } else {
                 NetdUtils.setInterfaceDown(mNetd, iface);
             }
         } catch (IllegalStateException e) {
@@ -646,7 +646,7 @@
     }
 
     private void setInterfaceAdministrativeState(String iface, boolean up, EthernetCallback cb) {
-        if (mEthernetState == ETHERNET_STATE_DISABLED) {
+        if (!mIsEthernetEnabled) {
             cb.onError("Cannot enable/disable interface when ethernet is disabled");
             return;
         }
@@ -964,10 +964,9 @@
     @VisibleForTesting(visibility = PACKAGE)
     protected void setEthernetEnabled(boolean enabled) {
         mHandler.post(() -> {
-            int newState = enabled ? ETHERNET_STATE_ENABLED : ETHERNET_STATE_DISABLED;
-            if (mEthernetState == newState) return;
+            if (mIsEthernetEnabled == enabled) return;
 
-            mEthernetState = newState;
+            mIsEthernetEnabled = enabled;
 
             // Interface in server mode should also be included.
             ArrayList<String> interfaces =
@@ -985,26 +984,31 @@
                     NetdUtils.setInterfaceDown(mNetd, iface);
                 }
             }
-            broadcastEthernetStateChange(mEthernetState);
+            broadcastEthernetStateChange(mIsEthernetEnabled);
         });
     }
 
+    private int isEthernetEnabledAsInt(boolean state) {
+        return state ? ETHERNET_STATE_ENABLED : ETHERNET_STATE_DISABLED;
+    }
+
     private void unicastEthernetStateChange(@NonNull IEthernetServiceListener listener,
-            int state) {
+            boolean enabled) {
         ensureRunningOnEthernetServiceThread();
         try {
-            listener.onEthernetStateChanged(state);
+            listener.onEthernetStateChanged(isEthernetEnabledAsInt(enabled));
         } catch (RemoteException e) {
             // Do nothing here.
         }
     }
 
-    private void broadcastEthernetStateChange(int state) {
+    private void broadcastEthernetStateChange(boolean enabled) {
         ensureRunningOnEthernetServiceThread();
         final int n = mListeners.beginBroadcast();
         for (int i = 0; i < n; i++) {
             try {
-                mListeners.getBroadcastItem(i).onEthernetStateChanged(state);
+                mListeners.getBroadcastItem(i)
+                            .onEthernetStateChanged(isEthernetEnabledAsInt(enabled));
             } catch (RemoteException e) {
                 // Do nothing here.
             }
@@ -1016,7 +1020,7 @@
         postAndWaitForRunnable(() -> {
             pw.println(getClass().getSimpleName());
             pw.println("Ethernet State: "
-                    + (mEthernetState == ETHERNET_STATE_ENABLED ? "enabled" : "disabled"));
+                    + (mIsEthernetEnabled ? "enabled" : "disabled"));
             pw.println("Ethernet interface name filter: " + mIfaceMatch);
             pw.println("Interface used for tethering: " + mTetheringInterface);
             pw.println("Tethering interface mode: " + mTetheringInterfaceMode);
diff --git a/staticlibs/testutils/app/connectivitychecker/src/com/android/testutils/connectivitypreparer/ConnectivityCheckTest.kt b/staticlibs/testutils/app/connectivitychecker/src/com/android/testutils/connectivitypreparer/ConnectivityCheckTest.kt
index e634f0e..8e27c62 100644
--- a/staticlibs/testutils/app/connectivitychecker/src/com/android/testutils/connectivitypreparer/ConnectivityCheckTest.kt
+++ b/staticlibs/testutils/app/connectivitychecker/src/com/android/testutils/connectivitypreparer/ConnectivityCheckTest.kt
@@ -16,27 +16,167 @@
 
 package com.android.testutils.connectivitypreparer
 
+import android.Manifest.permission.NETWORK_SETTINGS
 import android.content.pm.PackageManager.FEATURE_TELEPHONY
 import android.content.pm.PackageManager.FEATURE_WIFI
+import android.net.LinkAddress
+import android.net.Network
+import android.net.NetworkCapabilities.NET_CAPABILITY_INTERNET
+import android.net.NetworkCapabilities.TRANSPORT_WIFI
+import android.net.NetworkRequest
+import android.net.wifi.WifiInfo
 import android.telephony.TelephonyManager
+import android.util.Log
 import androidx.test.ext.junit.runners.AndroidJUnit4
 import androidx.test.platform.app.InstrumentationRegistry
+import com.android.net.module.util.HexDump
+import com.android.net.module.util.NetworkStackConstants.IPV4_ADDR_ANY
+import com.android.net.module.util.NetworkStackConstants.IPV6_ADDR_ANY
+import com.android.testutils.AutoReleaseNetworkCallbackRule
 import com.android.testutils.ConnectUtil
+import com.android.testutils.RecorderCallback.CallbackEntry.CapabilitiesChanged
+import com.android.testutils.RecorderCallback.CallbackEntry.LinkPropertiesChanged
+import com.android.testutils.runAsShell
+import com.android.testutils.tryTest
+import java.io.IOException
+import java.net.DatagramPacket
+import java.net.DatagramSocket
+import java.util.Random
+import kotlin.test.assertFalse
+import kotlin.test.assertNotNull
 import kotlin.test.assertTrue
 import kotlin.test.fail
+import org.junit.Rule
 import org.junit.Test
 import org.junit.runner.RunWith
 
+private const val QUIC_SOCKET_TIMEOUT_MS = 5_000
+private const val QUIC_RETRY_COUNT = 5
+
 @RunWith(AndroidJUnit4::class)
 class ConnectivityCheckTest {
+    @get:Rule
+    val networkCallbackRule = AutoReleaseNetworkCallbackRule()
+
+    private val logTag = ConnectivityCheckTest::class.simpleName
     private val context by lazy { InstrumentationRegistry.getInstrumentation().context }
     private val pm by lazy { context.packageManager }
     private val connectUtil by lazy { ConnectUtil(context) }
 
+    // Skip IPv6 checks on virtual devices which do not support it. Tests that require IPv6 will
+    // still fail even if the preparer does not.
+    private fun ipv6Unsupported(wifiSsid: String?) = ConnectUtil.VIRTUAL_SSIDS.contains(
+        WifiInfo.sanitizeSsid(wifiSsid))
+
     @Test
     fun testCheckWifiSetup() {
         if (!pm.hasSystemFeature(FEATURE_WIFI)) return
         connectUtil.ensureWifiValidated()
+
+        val (wifiNetwork, wifiSsid) = runAsShell(NETWORK_SETTINGS) {
+            val cb = networkCallbackRule.requestNetwork(
+                NetworkRequest.Builder()
+                    .addTransportType(TRANSPORT_WIFI)
+                    .addCapability(NET_CAPABILITY_INTERNET)
+                    .build()
+            )
+            val capChanged = cb.eventuallyExpect<CapabilitiesChanged>(from = 0)
+            val network = capChanged.network
+            val ssid = capChanged.caps.ssid
+            assertFalse(ssid.isNullOrEmpty(), "No SSID for wifi network $network")
+            // Expect a global IPv6 address, and native or stacked IPv4
+            val lpChange = cb.history.poll(
+                pos = 0,
+                timeoutMs = 30_000L
+            ) {
+                it is LinkPropertiesChanged &&
+                it.network == network &&
+                it.lp.allLinkAddresses.any(LinkAddress::isIpv4) &&
+                        (ipv6Unsupported(ssid) || it.lp.hasGlobalIpv6Address())
+            }
+            assertNotNull(lpChange, "Wifi network $network needs an IPv4 address" +
+                    if (ipv6Unsupported(ssid)) "" else " and a global IPv6 address")
+
+            Pair(network, ssid)
+        }
+
+        // Checking QUIC is more important on Wi-Fi than cellular, as it finds firewall
+        // configuration problems on Wi-Fi, but cellular is not actionable by the test lab.
+        checkQuic(wifiNetwork, wifiSsid, ipv6 = false)
+        if (!ipv6Unsupported(wifiSsid)) {
+            checkQuic(wifiNetwork, wifiSsid, ipv6 = true)
+        }
+    }
+
+    /**
+     * Check that QUIC is working on the specified network.
+     *
+     * Some tests require QUIC (UDP), and some lab networks have been observed to not let it
+     * through due to firewalling. Ensure that devices are setup on a network that has the proper
+     * allowlists before trying to run the tests.
+     */
+    private fun checkQuic(network: Network, ssid: String, ipv6: Boolean) {
+        // Same endpoint as used in MultinetworkApiTest in CTS
+        val hostname = "connectivitycheck.android.com"
+        val targetAddrs = network.getAllByName(hostname)
+        val bindAddr = if (ipv6) IPV6_ADDR_ANY else IPV4_ADDR_ANY
+        if (targetAddrs.isEmpty()) {
+            Log.d(logTag, "No addresses found for $hostname")
+            return
+        }
+
+        val socket = DatagramSocket(0, bindAddr)
+        tryTest {
+            socket.soTimeout = QUIC_SOCKET_TIMEOUT_MS
+            network.bindSocket(socket)
+
+            // For reference see Version-Independent Properties of QUIC:
+            // https://datatracker.ietf.org/doc/html/rfc8999
+            // This packet just contains a long header with an unsupported version number, to force
+            // a version-negotiation packet in response.
+            val connectionId = ByteArray(8).apply { Random().nextBytes(this) }
+            val quicData = byteArrayOf(
+                // long header
+                0xc0.toByte(),
+                // version number (should be an unknown version for the server)
+                0xaa.toByte(), 0xda.toByte(), 0xca.toByte(), 0xca.toByte(),
+                // destination connection ID length
+                0x08,
+            ) + connectionId + byteArrayOf(
+                // source connection ID length
+                0x00,
+            ) + ByteArray(1185) // Ensure the packet is 1200 bytes long
+            val targetAddr = targetAddrs.firstOrNull { it.javaClass == bindAddr.javaClass }
+                ?: fail("No ${bindAddr.javaClass} found for $hostname " +
+                        "(got ${targetAddrs.joinToString()})")
+            repeat(QUIC_RETRY_COUNT) { i ->
+                socket.send(DatagramPacket(quicData, quicData.size, targetAddr, 443))
+
+                val receivedPacket = DatagramPacket(ByteArray(1500), 1500)
+                try {
+                    socket.receive(receivedPacket)
+                } catch (e: IOException) {
+                    Log.d(logTag, "No response from $hostname ($targetAddr) on QUIC try $i", e)
+                    return@repeat
+                }
+
+                val receivedConnectionId = receivedPacket.data.copyOfRange(7, 7 + 8)
+                if (connectionId.contentEquals(receivedConnectionId)) {
+                    return@tryTest
+                } else {
+                    val headerBytes = receivedPacket.data.copyOfRange(
+                        0, receivedPacket.length.coerceAtMost(15))
+                    Log.d(logTag, "Received invalid connection ID on QUIC try $i: " +
+                            HexDump.toHexString(headerBytes))
+                }
+            }
+            fail("QUIC is not working on SSID $ssid connecting to $targetAddr " +
+                    "with local source port ${socket.localPort}: check the firewall for UDP port " +
+                    "443 access."
+            )
+        } cleanup {
+            socket.close()
+        }
     }
 
     @Test
@@ -53,12 +193,16 @@
         if (tm.simState == TelephonyManager.SIM_STATE_ABSENT) {
             fail("The device has no SIM card inserted. $commonError")
         } else if (tm.simState != TelephonyManager.SIM_STATE_READY) {
-            fail("The device is not setup with a usable SIM card. Sim state was ${tm.simState}. " +
-                    commonError)
+            fail(
+                "The device is not setup with a usable SIM card. Sim state was ${tm.simState}. " +
+                    commonError
+            )
         }
-        assertTrue(tm.isDataConnectivityPossible,
+        assertTrue(
+            tm.isDataConnectivityPossible,
             "The device has a SIM card, but it does not supports data connectivity. " +
-            "Check the data plan, and verify that mobile data is working. " + commonError)
+            "Check the data plan, and verify that mobile data is working. " + commonError
+        )
         connectUtil.ensureCellularValidated()
     }
 }
diff --git a/staticlibs/testutils/devicetests/com/android/testutils/ConnectUtil.kt b/staticlibs/testutils/devicetests/com/android/testutils/ConnectUtil.kt
index 3857810..d60ab59 100644
--- a/staticlibs/testutils/devicetests/com/android/testutils/ConnectUtil.kt
+++ b/staticlibs/testutils/devicetests/com/android/testutils/ConnectUtil.kt
@@ -53,6 +53,10 @@
 private const val WIFI_ERROR_BUSY = 2
 
 class ConnectUtil(private val context: Context) {
+    companion object {
+        @JvmStatic
+        val VIRTUAL_SSIDS = listOf("VirtWifi", "AndroidWifi")
+    }
     private val TAG = ConnectUtil::class.java.simpleName
 
     private val cm = context.getSystemService(ConnectivityManager::class.java)
@@ -207,9 +211,8 @@
      */
     private fun maybeConfigureVirtualNetwork(scanResults: List<ScanResult>): WifiConfiguration? {
         // Virtual wifi networks used on the emulator and cloud testing infrastructure
-        val virtualSsids = listOf("VirtWifi", "AndroidWifi")
         Log.d(TAG, "Wifi scan results: $scanResults")
-        val virtualScanResult = scanResults.firstOrNull { virtualSsids.contains(it.SSID) }
+        val virtualScanResult = scanResults.firstOrNull { VIRTUAL_SSIDS.contains(it.SSID) }
                 ?: return null
 
         // Only add the virtual configuration if the virtual AP is detected in scans
diff --git a/staticlibs/testutils/devicetests/com/android/testutils/DeviceInfoUtils.java b/staticlibs/testutils/devicetests/com/android/testutils/DeviceInfoUtils.java
index ce55fdc..31879af 100644
--- a/staticlibs/testutils/devicetests/com/android/testutils/DeviceInfoUtils.java
+++ b/staticlibs/testutils/devicetests/com/android/testutils/DeviceInfoUtils.java
@@ -16,6 +16,10 @@
 
 package com.android.testutils;
 
+import static com.android.modules.utils.build.SdkLevel.isAtLeastS;
+
+import android.os.Build;
+import android.os.SystemProperties;
 import android.os.VintfRuntimeInfo;
 import android.text.TextUtils;
 import android.util.Pair;
@@ -173,4 +177,14 @@
         final KVersion from = DeviceInfoUtils.getMajorMinorSubminorVersion(version);
         return current.isAtLeast(from);
     }
+
+    /**
+     * Check if the current build is a debuggable build.
+     */
+    public static boolean isDebuggable() {
+        if (isAtLeastS()) {
+            return Build.isDebuggable();
+        }
+        return SystemProperties.getInt("ro.debuggable", 0) == 1;
+    }
 }
diff --git a/staticlibs/testutils/hostdevice/com/android/testutils/MiscAsserts.kt b/staticlibs/testutils/hostdevice/com/android/testutils/MiscAsserts.kt
index d1d5649..176546a 100644
--- a/staticlibs/testutils/hostdevice/com/android/testutils/MiscAsserts.kt
+++ b/staticlibs/testutils/hostdevice/com/android/testutils/MiscAsserts.kt
@@ -20,6 +20,7 @@
 
 import com.android.testutils.FunctionalUtils.ThrowingRunnable
 import java.lang.reflect.Modifier
+import java.util.concurrent.TimeUnit
 import java.util.function.BooleanSupplier
 import kotlin.system.measureTimeMillis
 import kotlin.test.assertEquals
@@ -134,7 +135,7 @@
     // on host). When waiting for a condition during tests the device would generally not go into
     // deep sleep, and the polling sleep would go over the timeout anyway in that case, so this is
     // fine.
-    val limit = System.nanoTime() + timeoutMs * 1000
+    val limit = System.nanoTime() + TimeUnit.MILLISECONDS.toNanos(timeoutMs)
     while (!fn.asBoolean) {
         if (System.nanoTime() > limit) {
             fail(descr)
diff --git a/tests/cts/net/src/android/net/cts/ConnectivityManagerTest.java b/tests/cts/net/src/android/net/cts/ConnectivityManagerTest.java
index 88309ed..feb4621 100644
--- a/tests/cts/net/src/android/net/cts/ConnectivityManagerTest.java
+++ b/tests/cts/net/src/android/net/cts/ConnectivityManagerTest.java
@@ -952,9 +952,8 @@
         final List<InetAddress> cellNetworkAddresses = cellLinkProperties.getAddresses();
         // In userdebug build, on cellular network, if the onNetwork check failed, we also try to
         // re-verify it by obtaining the IP address through DNS query.
-        boolean isUserDebug = Build.isDebuggable();
         if (cellAddress instanceof Inet6Address) {
-            if (isUserDebug && !cellNetworkAddresses.contains(cellAddress)) {
+            if (DeviceInfoUtils.isDebuggable() && !cellNetworkAddresses.contains(cellAddress)) {
                 final InetAddress ipv6AddressThroughDns = InetAddresses.parseNumericAddress(
                         getDeviceIpv6AddressThroughDnsQuery(cellNetwork));
                 assertContains(cellNetworkAddresses, ipv6AddressThroughDns);