diff --git a/core/java/android/app/Instrumentation.java b/core/java/android/app/Instrumentation.java
index 2162e3a..68512b8 100644
--- a/core/java/android/app/Instrumentation.java
+++ b/core/java/android/app/Instrumentation.java
@@ -79,6 +79,7 @@
  * implementation is described to the system through an AndroidManifest.xml's
  * &lt;instrumentation&gt; tag.
  */
+@android.ravenwood.annotation.RavenwoodKeepPartialClass
 public class Instrumentation {
 
     /**
@@ -132,6 +133,7 @@
     private UiAutomation mUiAutomation;
     private final Object mAnimationCompleteLock = new Object();
 
+    @android.ravenwood.annotation.RavenwoodKeep
     public Instrumentation() {
     }
 
@@ -142,6 +144,7 @@
      * reflection, but it will serve as noticeable discouragement from
      * doing such a thing.
      */
+    @android.ravenwood.annotation.RavenwoodReplace
     private void checkInstrumenting(String method) {
         // Check if we have an instrumentation context, as init should only get called by
         // the system in startup processes that are being instrumented.
@@ -151,6 +154,11 @@
         }
     }
 
+    private void checkInstrumenting$ravenwood(String method) {
+        // At the moment, Ravenwood doesn't attach a Context, but we're only ever
+        // running code as part of tests, so we continue quietly
+    }
+
     /**
      * Returns if it is being called in an instrumentation environment.
      *
@@ -2504,6 +2512,7 @@
      * Takes control of the execution of messages on the specified looper until
      * {@link TestLooperManager#release} is called.
      */
+    @android.ravenwood.annotation.RavenwoodKeep
     public TestLooperManager acquireLooperManager(Looper looper) {
         checkInstrumenting("acquireLooperManager");
         return new TestLooperManager(looper);
diff --git a/core/java/android/os/TestLooperManager.java b/core/java/android/os/TestLooperManager.java
index 5e7549f..4b16c1d 100644
--- a/core/java/android/os/TestLooperManager.java
+++ b/core/java/android/os/TestLooperManager.java
@@ -28,6 +28,7 @@
  * The test code may use {@link #next()} to acquire messages that have been queued to this
  * {@link Looper}/{@link MessageQueue} and then {@link #execute} to run any that desires.
  */
+@android.ravenwood.annotation.RavenwoodKeepWholeClass
 public class TestLooperManager {
 
     private static final ArraySet<Looper> sHeldLoopers = new ArraySet<>();
diff --git a/core/tests/coretests/src/android/os/BundleTest.java b/core/tests/coretests/src/android/os/BundleTest.java
index e7b5dff6..93c2e0e 100644
--- a/core/tests/coretests/src/android/os/BundleTest.java
+++ b/core/tests/coretests/src/android/os/BundleTest.java
@@ -20,6 +20,7 @@
 
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertNotNull;
 import static org.junit.Assert.assertThrows;
 import static org.junit.Assert.assertTrue;
 
@@ -121,6 +122,14 @@
     }
 
     @Test
+    public void testEmpty() throws Exception {
+        assertNotNull(Bundle.EMPTY);
+        assertEquals(0, Bundle.EMPTY.size());
+
+        new Bundle(Bundle.EMPTY);
+    }
+
+    @Test
     @IgnoreUnderRavenwood(blockedBy = ParcelFileDescriptor.class)
     public void testCreateFromParcel() throws Exception {
         boolean withFd;
diff --git a/core/tests/coretests/src/android/os/TestLooperManagerTest.java b/core/tests/coretests/src/android/os/TestLooperManagerTest.java
new file mode 100644
index 0000000..5959444
--- /dev/null
+++ b/core/tests/coretests/src/android/os/TestLooperManagerTest.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 android.os;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertNull;
+import static org.junit.Assert.assertTrue;
+
+import android.platform.test.ravenwood.RavenwoodRule;
+
+import androidx.test.platform.app.InstrumentationRegistry;
+import androidx.test.runner.AndroidJUnit4;
+
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.TimeUnit;
+
+@RunWith(AndroidJUnit4.class)
+public class TestLooperManagerTest {
+    private static final String TAG = "TestLooperManagerTest";
+
+    @Rule
+    public final RavenwoodRule mRavenwood = new RavenwoodRule.Builder()
+            .setProvideMainThread(true)
+            .build();
+
+    @Test
+    public void testMainThread() throws Exception {
+        doTest(Looper.getMainLooper());
+    }
+
+    @Test
+    public void testCustomThread() throws Exception {
+        final HandlerThread thread = new HandlerThread(TAG);
+        thread.start();
+        doTest(thread.getLooper());
+    }
+
+    private void doTest(Looper looper) throws Exception {
+        final TestLooperManager tlm =
+                InstrumentationRegistry.getInstrumentation().acquireLooperManager(looper);
+
+        final Handler handler = new Handler(looper);
+        final CountDownLatch latch = new CountDownLatch(1);
+
+        assertFalse(tlm.hasMessages(handler, null, 42));
+
+        handler.sendEmptyMessage(42);
+        handler.post(() -> {
+            latch.countDown();
+        });
+        assertTrue(tlm.hasMessages(handler, null, 42));
+        assertFalse(latch.await(100, TimeUnit.MILLISECONDS));
+
+        final Message first = tlm.next();
+        assertEquals(42, first.what);
+        assertNull(first.callback);
+        tlm.execute(first);
+        assertFalse(tlm.hasMessages(handler, null, 42));
+        assertFalse(latch.await(100, TimeUnit.MILLISECONDS));
+        tlm.recycle(first);
+
+        final Message second = tlm.next();
+        assertNotNull(second.callback);
+        tlm.execute(second);
+        assertFalse(tlm.hasMessages(handler, null, 42));
+        assertTrue(latch.await(100, TimeUnit.MILLISECONDS));
+        tlm.recycle(second);
+
+        tlm.release();
+    }
+}
diff --git a/ravenwood/Android.bp b/ravenwood/Android.bp
index e013a3e..1ac69f6 100644
--- a/ravenwood/Android.bp
+++ b/ravenwood/Android.bp
@@ -30,6 +30,9 @@
         "junit-src/**/*.java",
         "junit-impl-src/**/*.java",
     ],
+    static_libs: [
+        "androidx.test.monitor-for-device",
+    ],
     libs: [
         "framework-minus-apex.ravenwood",
         "junit",
@@ -61,3 +64,17 @@
         "core-xml-for-host",
     ],
 }
+
+java_host_for_device {
+    name: "androidx.test.monitor-for-device",
+    libs: [
+        "androidx.test.monitor-for-host",
+    ],
+}
+
+java_device_for_host {
+    name: "androidx.test.monitor-for-host",
+    libs: [
+        "androidx.test.monitor",
+    ],
+}
diff --git a/ravenwood/junit-impl-src/android/platform/test/ravenwood/RavenwoodRuleImpl.java b/ravenwood/junit-impl-src/android/platform/test/ravenwood/RavenwoodRuleImpl.java
index b3dbcde..a797b1d 100644
--- a/ravenwood/junit-impl-src/android/platform/test/ravenwood/RavenwoodRuleImpl.java
+++ b/ravenwood/junit-impl-src/android/platform/test/ravenwood/RavenwoodRuleImpl.java
@@ -16,12 +16,35 @@
 
 package android.platform.test.ravenwood;
 
+import android.app.Instrumentation;
+import android.os.Bundle;
 import android.os.HandlerThread;
 import android.os.Looper;
 
+import androidx.test.platform.app.InstrumentationRegistry;
+
+import java.io.PrintStream;
+import java.util.Map;
+import java.util.concurrent.Executors;
+import java.util.concurrent.ScheduledExecutorService;
+import java.util.concurrent.ScheduledFuture;
+import java.util.concurrent.TimeUnit;
+
 public class RavenwoodRuleImpl {
     private static final String MAIN_THREAD_NAME = "RavenwoodMain";
 
+    /**
+     * When enabled, attempt to dump all thread stacks just before we hit the
+     * overall Tradefed timeout, to aid in debugging deadlocks.
+     */
+    private static final boolean ENABLE_TIMEOUT_STACKS = false;
+    private static final int TIMEOUT_MILLIS = 9_000;
+
+    private static final ScheduledExecutorService sTimeoutExecutor =
+            Executors.newScheduledThreadPool(1);
+
+    private static ScheduledFuture<?> sPendingTimeout;
+
     public static boolean isOnRavenwood() {
         return true;
     }
@@ -41,9 +64,22 @@
             main.start();
             Looper.setMainLooperForTest(main.getLooper());
         }
+
+        InstrumentationRegistry.registerInstance(new Instrumentation(), Bundle.EMPTY);
+
+        if (ENABLE_TIMEOUT_STACKS) {
+            sPendingTimeout = sTimeoutExecutor.schedule(RavenwoodRuleImpl::dumpStacks,
+                    TIMEOUT_MILLIS, TimeUnit.MILLISECONDS);
+        }
     }
 
     public static void reset(RavenwoodRule rule) {
+        if (ENABLE_TIMEOUT_STACKS) {
+            sPendingTimeout.cancel(false);
+        }
+
+        InstrumentationRegistry.registerInstance(null, Bundle.EMPTY);
+
         if (rule.mProvideMainThread) {
             Looper.getMainLooper().quit();
             Looper.clearMainLooperForTest();
@@ -55,4 +91,19 @@
         android.os.Binder.reset$ravenwood();
         android.os.Process.reset$ravenwood();
     }
+
+    private static void dumpStacks() {
+        final PrintStream out = System.err;
+        out.println("-----BEGIN ALL THREAD STACKS-----");
+        final Map<Thread, StackTraceElement[]> stacks = Thread.getAllStackTraces();
+        for (Map.Entry<Thread, StackTraceElement[]> stack : stacks.entrySet()) {
+            out.println();
+            Thread t = stack.getKey();
+            out.println(t.toString() + " ID=" + t.getId());
+            for (StackTraceElement e : stack.getValue()) {
+                out.println("\tat " + e);
+            }
+        }
+        out.println("-----END ALL THREAD STACKS-----");
+    }
 }
diff --git a/ravenwood/ravenwood-annotation-allowed-classes.txt b/ravenwood/ravenwood-annotation-allowed-classes.txt
index eaf01a3..b775f9a 100644
--- a/ravenwood/ravenwood-annotation-allowed-classes.txt
+++ b/ravenwood/ravenwood-annotation-allowed-classes.txt
@@ -72,6 +72,7 @@
 android.os.ServiceSpecificException
 android.os.SystemClock
 android.os.SystemProperties
+android.os.TestLooperManager
 android.os.ThreadLocalWorkSource
 android.os.TimestampedValue
 android.os.Trace
@@ -141,6 +142,8 @@
 
 android.content.ContentProvider
 
+android.app.Instrumentation
+
 android.metrics.LogMaker
 
 android.view.Display$HdrCapabilities
diff --git a/tools/hoststubgen/hoststubgen/helper-framework-runtime-src/framework/com/android/hoststubgen/nativesubstitution/MessageQueue_host.java b/tools/hoststubgen/hoststubgen/helper-framework-runtime-src/framework/com/android/hoststubgen/nativesubstitution/MessageQueue_host.java
index 2e47d48..65da4a1 100644
--- a/tools/hoststubgen/hoststubgen/helper-framework-runtime-src/framework/com/android/hoststubgen/nativesubstitution/MessageQueue_host.java
+++ b/tools/hoststubgen/hoststubgen/helper-framework-runtime-src/framework/com/android/hoststubgen/nativesubstitution/MessageQueue_host.java
@@ -28,6 +28,7 @@
 
     private final Object mPoller = new Object();
     private volatile boolean mPolling;
+    private volatile boolean mPendingWake;
 
     private void validate() {
         if (mDeleted) {
@@ -62,7 +63,9 @@
         synchronized (q.mPoller) {
             q.mPolling = true;
             try {
-                if (timeoutMillis == 0) {
+                if (q.mPendingWake) {
+                    // Calling with pending wake returns immediately
+                } else if (timeoutMillis == 0) {
                     // Calling epoll_wait() with 0 returns immediately
                 } else if (timeoutMillis == -1) {
                     q.mPoller.wait();
@@ -72,6 +75,8 @@
             } catch (InterruptedException e) {
                 Thread.currentThread().interrupt();
             }
+            // Any reason for returning counts as a "wake", so clear pending
+            q.mPendingWake = false;
             q.mPolling = false;
         }
     }
@@ -79,6 +84,7 @@
     public static void nativeWake(long ptr) {
         var q = getInstance(ptr);
         synchronized (q.mPoller) {
+            q.mPendingWake = true;
             q.mPoller.notifyAll();
         }
     }