diff --git a/camera/ndk/NdkCameraCaptureSession.cpp b/camera/ndk/NdkCameraCaptureSession.cpp
index e6c876b..4387cc6 100644
--- a/camera/ndk/NdkCameraCaptureSession.cpp
+++ b/camera/ndk/NdkCameraCaptureSession.cpp
@@ -194,24 +194,19 @@
 
 EXPORT
 camera_status_t ACameraCaptureSession_setWindowPreparedCallback(
-        ACameraCaptureSession* session, ACameraCaptureSession_prepareCallbacks *cb) {
+        ACameraCaptureSession* session, void *context,
+        ACameraCaptureSession_prepareCallback cb) {
     ATRACE_CALL();
     if (session == nullptr || cb == nullptr) {
         ALOGE("%s: Error: session %p / callback %p is null", __FUNCTION__, session, cb);
         return ACAMERA_ERROR_INVALID_PARAMETER;
     }
 
-    if (cb->reserved0 != nullptr || cb->reserved1 != nullptr) {
-         ALOGE("%s: Setting reserved 0 and reserved 1 fields of "
-               "ACameraCaptureSession_prepareCallbacks is currently not supported "
-               " .They must be set to  null", __FUNCTION__);
-        return ACAMERA_ERROR_INVALID_PARAMETER;
-    }
     if (session->isClosed()) {
         ALOGE("%s: session %p is already closed", __FUNCTION__, session);
         return ACAMERA_ERROR_SESSION_CLOSED;
     }
-    session->setWindowPreparedCallback(cb);
+    session->setWindowPreparedCallback(context, cb);
     return ACAMERA_OK;
 }
 
diff --git a/camera/ndk/impl/ACameraCaptureSession.h b/camera/ndk/impl/ACameraCaptureSession.h
index 145473b..88135ba 100644
--- a/camera/ndk/impl/ACameraCaptureSession.h
+++ b/camera/ndk/impl/ACameraCaptureSession.h
@@ -75,6 +75,17 @@
 };
 
 /**
+ * Capture session state callbacks used in {@link ACameraDevice_setPrepareCallbacks}
+ */
+typedef struct ACameraCaptureSession_prepareCallbacks {
+    /// optional application context. This will be passed in the context
+    /// parameter of the {@link onWindowPrepared} callback.
+    void*                               context;
+
+    ACameraCaptureSession_prepareCallback onWindowPrepared;
+} ACameraCaptureSession_prepareCallbacks;
+
+/**
  * ACameraCaptureSession opaque struct definition
  * Leave outside of android namespace because it's NDK struct
  */
@@ -130,9 +141,11 @@
 
     camera_status_t updateOutputConfiguration(ACaptureSessionOutput *output);
 
-    void setWindowPreparedCallback(ACameraCaptureSession_prepareCallbacks *cb) {
+    void setWindowPreparedCallback(void *context,
+            ACameraCaptureSession_prepareCallback cb) {
         Mutex::Autolock _l(mSessionLock);
-        mPreparedCb = *cb;
+        mPreparedCb.context = context;
+        mPreparedCb.onWindowPrepared = cb;
     }
     camera_status_t prepare(ACameraWindowType *window);
 
diff --git a/camera/ndk/include/camera/NdkCameraCaptureSession.h b/camera/ndk/include/camera/NdkCameraCaptureSession.h
index 0211d83..5f29910 100644
--- a/camera/ndk/include/camera/NdkCameraCaptureSession.h
+++ b/camera/ndk/include/camera/NdkCameraCaptureSession.h
@@ -101,6 +101,20 @@
 
 /**
  * The definition of camera capture session onWindowPrepared callback.
+ *
+ * <p>This callback is called when the buffer pre-allocation for an output window Surface is
+ * complete. </p>
+ *
+ * <p>Buffer pre-allocation for an output window is started by
+ * {@link ACameraCaptureSession_prepare}
+ * call. While allocation is underway, the output must not be used in a capture request.
+ * Once this callback is called, the output provided can be used as a target for a
+ * capture request. In case of an error during pre-allocation (such as running out of
+ * suitable-memory), this callback is still invoked after the error is encountered, though some
+ * buffers may not have been successfully pre-allocated.</p>
+ *
+ * Introduced in API 34.
+ *
  * @param context The optional app-provided context pointer that was included in
  *        the {@link ACameraCaptureSession_prepareCallbacks} struct.
  * @param window The window that {@link ACameraCaptureSession_prepare} was called on.
@@ -112,32 +126,6 @@
         ACameraWindowType *window,
         ACameraCaptureSession *session);
 
-/**
- * Capture session state callbacks used in {@link ACameraDevice_setPrepareCallbacks}
- */
-typedef struct ACameraCaptureSession_prepareCallbacks {
-    /// optional application context. This will be passed in the context
-    /// parameter of the {@link onWindowPrepared} callback.
-    void*                               context;
-
-    /**
-     * This callback is called when the buffer pre-allocation for an output window Surface is
-     * complete.
-     * <p>Buffer pre-allocation for an output window is started by
-     * {@link ACameraCaptureSession_prepare}
-     * call. While allocation is underway, the output must not be used in a capture request.
-     * Once this callback is called, the output provided can be used as a target for a
-     * capture request. In case of an error during pre-allocation (such as running out of
-     * suitable-memory), this callback is still invoked after the error is encountered, though some
-     * buffers may not have been successfully pre-allocated </p>
-     */
-    ACameraCaptureSession_prepareCallback onWindowPrepared;
-
-    // Reserved for future callback additions, these must be set to nullptr by the client.
-    ACameraCaptureSession_prepareCallback reserved0;
-    ACameraCaptureSession_prepareCallback reserved1;
-} ACameraCaptureSession_prepareCallbacks;
-
 /// Enum for describing error reason in {@link ACameraCaptureFailure}
 enum {
     /**
@@ -1033,8 +1021,10 @@
  * pre-allocation of buffers through the {@link ACameraCaptureSession_prepareWindow} call has
  * completed the pre-allocation of buffers.
  * @param session the ACameraCaptureSession on which ACameraCaptureSession_prepareWindow was called.
- * @param callbacks the callback to be called when the output window's buffer pre-allocation is
- *                  complete.
+ * @param context optional application provided context. This will be passed into the context
+ *        parameter of the {@link onWindowPrepared} callback.
+ * @param callback the callback to be called when the output window's buffer pre-allocation is
+ *        complete.
  * @return <ul><li> {@link ACAMERA_OK} if the method succeeds</li>
  *         <li>{@link ACAMERA_ERROR_INVALID_PARAMETER} if session or callbacks is
  *              NULL. Or if the session has not been configured with the window</li>
@@ -1046,7 +1036,8 @@
  */
 camera_status_t ACameraCaptureSession_setWindowPreparedCallback(
     ACameraCaptureSession* session,
-    ACameraCaptureSession_prepareCallbacks* callbacks) __INTRODUCED_IN(34);
+    void *context,
+    ACameraCaptureSession_prepareCallback callback) __INTRODUCED_IN(34);
 
 /**
  *
@@ -1087,7 +1078,7 @@
  * <p>Once allocation is complete, {@link ACameraCaptureSession_prepareCallback#onWindowPrepared}
  * will be invoked with the output provided to this method. Between the prepare call and the
  * {@link ACameraCaptureSession_prepareCallback#onWindowPrepared} call,
- * the output provided to prepare must not be used as a target of a capture qequest submitted
+ * the output provided to prepare must not be used as a target of a capture request submitted
  * to this session.</p>
  *
  * <p>{@link android.hardware.camera2.CameraCharacteristics#INFO_SUPPORTED_HARDWARE_LEVEL_LEGACY LEGACY}
diff --git a/camera/ndk/ndk_vendor/tests/AImageReaderVendorTest.cpp b/camera/ndk/ndk_vendor/tests/AImageReaderVendorTest.cpp
index 00d66aa..7f6ea9d 100644
--- a/camera/ndk/ndk_vendor/tests/AImageReaderVendorTest.cpp
+++ b/camera/ndk/ndk_vendor/tests/AImageReaderVendorTest.cpp
@@ -144,7 +144,8 @@
         }
         if (prepareWindows) {
             // Set window prepared callback
-            ACameraCaptureSession_setWindowPreparedCallback(mSession, &mPreparedCb);
+            ACameraCaptureSession_setWindowPreparedCallback(mSession, /*context*/this,
+                    mPreparedCb);
             // Prepare windows
             for (auto &window : configuredWindows) {
                 ret = ACameraCaptureSession_prepareWindow(mSession, window);
@@ -342,8 +343,7 @@
     ACameraDevice_StateCallbacks mDeviceCb{this, nullptr, nullptr};
     ACameraCaptureSession_stateCallbacks mSessionCb{ this, nullptr, nullptr, nullptr};
 
-    ACameraCaptureSession_prepareCallbacks mPreparedCb{
-            this, onPreparedCb, /*reserved0*/nullptr, /*reserved1*/nullptr};
+    ACameraCaptureSession_prepareCallback mPreparedCb = &onPreparedCb;
 
     const native_handle_t* mImgReaderAnw = nullptr;  // not owned by us.