diff --git a/ReactAndroid/src/main/jni/react/jni/ProxyExecutor.cpp b/ReactAndroid/src/main/jni/react/jni/ProxyExecutor.cpp
index 7cbc68490b7e..1f48fb0ea4e3 100644
--- a/ReactAndroid/src/main/jni/react/jni/ProxyExecutor.cpp
+++ b/ReactAndroid/src/main/jni/react/jni/ProxyExecutor.cpp
@@ -49,7 +49,7 @@ ProxyExecutor::~ProxyExecutor() {
   m_executor.reset();
 }
 
-void ProxyExecutor::setupEnvironment(std::function<void(std::string, bool)> loadBundle,
+void ProxyExecutor::setupEnvironment(std::function<void(std::string, bool, bool)> loadBundle,
                                      std::function<RAMBundle::Module(uint32_t, std::string)> getModule) {
   // TODO: what is this ProxyExecutor?
 }
diff --git a/ReactAndroid/src/main/jni/react/jni/ProxyExecutor.h b/ReactAndroid/src/main/jni/react/jni/ProxyExecutor.h
index 421fcb80265c..7f699ff16344 100644
--- a/ReactAndroid/src/main/jni/react/jni/ProxyExecutor.h
+++ b/ReactAndroid/src/main/jni/react/jni/ProxyExecutor.h
@@ -35,11 +35,10 @@ class ProxyExecutor : public JSExecutor {
   ProxyExecutor(jni::global_ref<jobject>&& executorInstance,
                 std::shared_ptr<ExecutorDelegate> delegate);
   virtual ~ProxyExecutor() override;
-  virtual void setupEnvironment(std::function<void(std::string, bool)> loadBundle,
+  virtual void setupEnvironment(std::function<void(std::string, bool, bool)> loadBundle,
                                 std::function<RAMBundle::Module(uint32_t, std::string)> getModule) override;
-  virtual void loadScript(
-    std::unique_ptr<const JSBigString> script,
-    std::string sourceURL) override;
+  virtual void loadScript(std::unique_ptr<const JSBigString> script,
+                          std::string sourceURL) override;
   virtual void callFunction(
     const std::string& moduleId,
     const std::string& methodId,
diff --git a/ReactCommon/cxxreact/BundleRegistry.cpp b/ReactCommon/cxxreact/BundleRegistry.cpp
index 659e2339c211..24d1409a3a0f 100644
--- a/ReactCommon/cxxreact/BundleRegistry.cpp
+++ b/ReactCommon/cxxreact/BundleRegistry.cpp
@@ -1,4 +1,5 @@
 #include "BundleRegistry.h"
+#include <folly/dynamic.h>
 
 namespace facebook {
 namespace react {
@@ -160,10 +161,11 @@ BundleRegistry::GetModuleLambda BundleRegistry::makeGetModuleLambda(std::string
 }
 
 BundleRegistry::LoadBundleLambda BundleRegistry::makeLoadBundleLambda(std::string environmentId) {
-  return [this, environmentId](std::string bundleName, bool inCurrentEnvironment) mutable {
+  return [this, environmentId](std::string bundleName, bool sync, bool inCurrentEnvironment) mutable {
     std::shared_ptr<BundleExecutionEnvironment> execEnv = getEnvironment(environmentId).lock();
     std::string bundleURL = bundleLoader_->getBundleURLFromName(bundleName);
-    execEnv->jsQueue->runOnQueueSync([this, bundleURL, execEnv]() mutable {
+
+    std::function<void()> loadAndEvalBundle = [this, bundleName, bundleURL, execEnv, sync]() mutable {
       std::unique_ptr<const Bundle> additionalBundle = bundleLoader_->getBundle(bundleURL);
       bundles_[bundleURL] = std::move(additionalBundle);
       std::shared_ptr<const Bundle> bundle = bundles_[bundleURL];
@@ -171,7 +173,18 @@ BundleRegistry::LoadBundleLambda BundleRegistry::makeLoadBundleLambda(std::strin
 
       execEnv->nativeToJsBridge->loadScriptSync(std::move(script),
                                                 bundle->getSourceURL());
-    });
+      if (!sync) {
+        execEnv->nativeToJsBridge->callFunction("BundleRegistry",
+                                                "bundleRegistryOnLoad",
+                                                folly::dynamic::array(bundleName));
+      }
+    };
+
+    if (sync) {
+      execEnv->jsQueue->runOnQueueSync(std::move(loadAndEvalBundle));
+    } else {
+      execEnv->jsQueue->runOnQueue(std::move(loadAndEvalBundle));
+    }
   };
 }
 
diff --git a/ReactCommon/cxxreact/BundleRegistry.h b/ReactCommon/cxxreact/BundleRegistry.h
index a59356c6aa9c..e0de3c6b40c6 100644
--- a/ReactCommon/cxxreact/BundleRegistry.h
+++ b/ReactCommon/cxxreact/BundleRegistry.h
@@ -15,7 +15,7 @@ class ModuleRegistry;
 
 class BundleRegistry {
   public:
-    using LoadBundleLambda = std::function<void(std::string bundleName, bool inCurrentEnvironment)>;
+    using LoadBundleLambda = std::function<void(std::string bundleName, bool sync, bool inCurrentEnvironment)>;
     using GetModuleLambda = std::function<RAMBundle::Module(uint32_t moduleId, std::string bundleName)>;
 
     struct BundleExecutionEnvironment {
diff --git a/ReactCommon/cxxreact/JSExecutor.h b/ReactCommon/cxxreact/JSExecutor.h
index 514d48fc8828..aa5a61929c19 100644
--- a/ReactCommon/cxxreact/JSExecutor.h
+++ b/ReactCommon/cxxreact/JSExecutor.h
@@ -55,7 +55,7 @@ class RN_EXPORT JSExecutor {
    * Should be called only once per JSContext.
    * Sets: nativeRequire (if bundle is RAM), bundleRegistryLoad
    */
-  virtual void setupEnvironment(std::function<void(std::string, bool)> loadBundle,
+  virtual void setupEnvironment(std::function<void(std::string, bool, bool)> loadBundle,
                                 std::function<RAMBundle::Module(uint32_t, std::string)> getModule) = 0;
 
   /**
diff --git a/ReactCommon/cxxreact/NativeToJsBridge.cpp b/ReactCommon/cxxreact/NativeToJsBridge.cpp
index 1deac434cf98..e076defcc337 100644
--- a/ReactCommon/cxxreact/NativeToJsBridge.cpp
+++ b/ReactCommon/cxxreact/NativeToJsBridge.cpp
@@ -98,14 +98,14 @@ NativeToJsBridge::~NativeToJsBridge() {
     "NativeToJsBridge::destroy() must be called before deallocating the NativeToJsBridge!";
 }
 
-void NativeToJsBridge::setupEnvironment(std::function<void(std::string, bool)> loadBundle,
+void NativeToJsBridge::setupEnvironment(std::function<void(std::string, bool, bool)> loadBundle,
                                         std::function<RAMBundle::Module(uint32_t, std::string)> getModule) {
   runOnExecutorQueue([this, loadBundle, getModule](JSExecutor* executor) mutable {
     m_executor->setupEnvironment(loadBundle, getModule);
   });
 }
 
-void NativeToJsBridge::setupEnvironmentSync(std::function<void(std::string, bool)> loadBundle,
+void NativeToJsBridge::setupEnvironmentSync(std::function<void(std::string, bool, bool)> loadBundle,
                                             std::function<RAMBundle::Module(uint32_t, std::string)> getModule) {
   m_executor->setupEnvironment(loadBundle, getModule);
 }
diff --git a/ReactCommon/cxxreact/NativeToJsBridge.h b/ReactCommon/cxxreact/NativeToJsBridge.h
index 0cad47233043..5fe6cb37fd91 100644
--- a/ReactCommon/cxxreact/NativeToJsBridge.h
+++ b/ReactCommon/cxxreact/NativeToJsBridge.h
@@ -62,10 +62,10 @@ class NativeToJsBridge {
    * Prepare JSExecutor environment for evaluating JS.
    * Should be called only once per JSExecutor.
    */
-  void setupEnvironment(std::function<void(std::string, bool)> loadBundle,
+  void setupEnvironment(std::function<void(std::string, bool, bool)> loadBundle,
                         std::function<RAMBundle::Module(uint32_t, std::string)> getModule);
   
-  void setupEnvironmentSync(std::function<void(std::string, bool)> loadBundle,
+  void setupEnvironmentSync(std::function<void(std::string, bool, bool)> loadBundle,
                             std::function<RAMBundle::Module(uint32_t, std::string)> getModule);
 
   /**
diff --git a/ReactCommon/jsiexecutor/jsireact/JSIExecutor.cpp b/ReactCommon/jsiexecutor/jsireact/JSIExecutor.cpp
index ed4393dcb2ed..92573d010d38 100644
--- a/ReactCommon/jsiexecutor/jsireact/JSIExecutor.cpp
+++ b/ReactCommon/jsiexecutor/jsireact/JSIExecutor.cpp
@@ -69,7 +69,7 @@ JSIExecutor::JSIExecutor(
       *runtime, "__jsiExecutorDescription", runtime->description());
 }
 
-void JSIExecutor::setupEnvironment(std::function<void(std::string, bool)> loadBundle,
+void JSIExecutor::setupEnvironment(std::function<void(std::string, bool, bool)> loadBundle,
                                    std::function<RAMBundle::Module(uint32_t, std::string)> getModule) {
   SystraceSection s("JSIExecutor::setupEnvironment");
 
@@ -117,18 +117,19 @@ void JSIExecutor::setupEnvironment(std::function<void(std::string, bool)> loadBu
     Function::createFromHostFunction(
       *runtime_,
       PropNameID::forAscii(*runtime_, "bundleRegistryLoad"),
-      2,
+      3,
       [this, loadBundle](jsi::Runtime&,
              const jsi::Value&,
              const jsi::Value* args,
              size_t count) {
-        if (count != 2) {
+        if (count != 3) {
           throw std::invalid_argument("Got wrong number of args");
         }
 
         std::string bundleName = args[0].getString(*runtime_).utf8(*runtime_);
+        bool sync = args[1].getBool();
         bool inCurrentEnvironment = args[1].getBool();
-        loadBundle(bundleName, inCurrentEnvironment);
+        loadBundle(bundleName, sync, inCurrentEnvironment);
 
         return facebook::jsi::Value();
       }));
diff --git a/ReactCommon/jsiexecutor/jsireact/JSIExecutor.h b/ReactCommon/jsiexecutor/jsireact/JSIExecutor.h
index cadd2004a8e5..b568e75ebda0 100644
--- a/ReactCommon/jsiexecutor/jsireact/JSIExecutor.h
+++ b/ReactCommon/jsiexecutor/jsireact/JSIExecutor.h
@@ -78,11 +78,10 @@ class JSIExecutor : public JSExecutor {
       Logger logger,
       const JSIScopedTimeoutInvoker& timeoutInvoker,
       RuntimeInstaller runtimeInstaller);
-  void setupEnvironment(std::function<void(std::string, bool)> loadBundle,
+  void setupEnvironment(std::function<void(std::string, bool, bool)> loadBundle,
                         std::function<RAMBundle::Module(uint32_t, std::string)> getModule) override;
-  void loadScript(
-      std::unique_ptr<const JSBigString> script,
-      std::string sourceURL) override;
+  void loadScript(std::unique_ptr<const JSBigString> script,
+                  std::string sourceURL) override;
   void callFunction(
       const std::string& moduleId,
       const std::string& methodId,