diff --git a/deps/v8/src/globals.h b/deps/v8/src/globals.h
index e06257d35e..6f2b748e01 100644
--- a/deps/v8/src/globals.h
+++ b/deps/v8/src/globals.h
@@ -629,6 +629,8 @@ enum VisitMode {
   VISIT_ALL_IN_MINOR_MC_UPDATE,
   VISIT_ALL_IN_SCAVENGE,
   VISIT_ALL_IN_SWEEP_NEWSPACE,
+  VISIT_ALL_FOR_STARTUP_DESERIALIZATION,
+  VISIT_ALL_FOR_STARTUP_SERIALIZATION,
   VISIT_ONLY_STRONG,
   VISIT_ONLY_STRONG_FOR_SERIALIZATION,
   VISIT_ONLY_STRONG_ROOT_LIST,
diff --git a/deps/v8/src/heap/heap-inl.h b/deps/v8/src/heap/heap-inl.h
index 49d69c80e2..d558434850 100644
--- a/deps/v8/src/heap/heap-inl.h
+++ b/deps/v8/src/heap/heap-inl.h
@@ -25,6 +25,7 @@
 #include "src/objects/scope-info.h"
 #include "src/objects/script-inl.h"
 #include "src/profiler/heap-profiler.h"
+#include "src/snapshot/startup-serializer.h"
 #include "src/string-hasher.h"
 
 namespace v8 {
@@ -585,6 +586,27 @@ void Heap::ExternalStringTable::IterateAll(RootVisitor* v) {
   }
 }
 
+void Heap::ExternalStringTable::IterateAll(RootVisitor* v, VisitMode mode) {
+  if (mode == VISIT_ALL_FOR_STARTUP_DESERIALIZATION) {
+    StartupSerializer::IterateExternalStringTable(heap_->isolate_, &new_space_strings_, v);
+    StartupSerializer::IterateExternalStringTable(heap_->isolate_, &old_space_strings_, v);
+  } else if (mode == VISIT_ALL_FOR_STARTUP_SERIALIZATION) {
+    Object* undefined = heap_->undefined_value();
+    IterateNewSpaceStrings(v);
+    // end sentinel
+    v->VisitRootPointer(Root::kExternalStringsTable, &undefined);
+
+    if (!old_space_strings_.empty()) {
+      v->VisitRootPointers(Root::kExternalStringsTable, old_space_strings_.data(),
+          old_space_strings_.data() + old_space_strings_.size());
+    }
+    // end sentinel
+    v->VisitRootPointer(Root::kExternalStringsTable, &undefined);
+  } else {
+    IterateAll(v);
+  }
+}
+
 
 // Verify() is inline to avoid ifdef-s around its calls in release
 // mode.
diff --git a/deps/v8/src/heap/heap.cc b/deps/v8/src/heap/heap.cc
index b13ec784f5..99725c9be5 100644
--- a/deps/v8/src/heap/heap.cc
+++ b/deps/v8/src/heap/heap.cc
@@ -5266,7 +5266,7 @@ void Heap::IterateWeakRoots(RootVisitor* v, VisitMode mode) {
   v->Synchronize(VisitorSynchronization::kStringTable);
   if (!isMinorGC && mode != VISIT_ALL_IN_SWEEP_NEWSPACE) {
     // Scavenge collections have special processing for this.
-    external_string_table_.IterateAll(v);
+    external_string_table_.IterateAll(v, mode);
   }
   v->Synchronize(VisitorSynchronization::kExternalStringsTable);
 }
diff --git a/deps/v8/src/heap/heap.h b/deps/v8/src/heap/heap.h
index 7b87770385..adc7d5cb24 100644
--- a/deps/v8/src/heap/heap.h
+++ b/deps/v8/src/heap/heap.h
@@ -1564,6 +1564,7 @@ class Heap {
     inline void AddString(String* string);
 
     inline void IterateAll(RootVisitor* v);
+    inline void IterateAll(RootVisitor* v, VisitMode mode);
     inline void IterateNewSpaceStrings(RootVisitor* v);
     inline void PromoteAllNewSpaceStrings();
 
diff --git a/deps/v8/src/snapshot/startup-deserializer.cc b/deps/v8/src/snapshot/startup-deserializer.cc
index 6746a02656..5934b7db27 100644
--- a/deps/v8/src/snapshot/startup-deserializer.cc
+++ b/deps/v8/src/snapshot/startup-deserializer.cc
@@ -30,7 +30,7 @@ void StartupDeserializer::DeserializeInto(Isolate* isolate) {
     isolate->heap()->IterateSmiRoots(this);
     isolate->heap()->IterateStrongRoots(this, VISIT_ONLY_STRONG);
     isolate->heap()->RepairFreeListsAfterDeserialization();
-    isolate->heap()->IterateWeakRoots(this, VISIT_ALL);
+    isolate->heap()->IterateWeakRoots(this, VISIT_ALL_FOR_STARTUP_DESERIALIZATION);
     DeserializeDeferredObjects();
     FlushICacheForNewIsolate();
     RestoreExternalReferenceRedirectors(accessor_infos());
diff --git a/deps/v8/src/snapshot/startup-serializer.cc b/deps/v8/src/snapshot/startup-serializer.cc
index e2bd4ceadd..c36d8ef068 100644
--- a/deps/v8/src/snapshot/startup-serializer.cc
+++ b/deps/v8/src/snapshot/startup-serializer.cc
@@ -26,6 +26,17 @@ StartupSerializer::~StartupSerializer() {
   OutputStatistics("StartupSerializer");
 }
 
+void StartupSerializer::IterateExternalStringTable(Isolate* isolate,
+                                                   std::vector<Object*>* strings,
+                                                   RootVisitor* visitor) {
+  for (size_t i = 0;; ++i) {
+    Object* obj;
+    visitor->VisitRootPointer(Root::kExternalStringsTable, &obj);
+    if (obj->IsUndefined(isolate)) break;
+    if (obj->IsExternalString()) strings->push_back(obj);
+  }
+}
+
 void StartupSerializer::SerializeObject(HeapObject* obj, HowToCode how_to_code,
                                         WhereToPoint where_to_point, int skip) {
   DCHECK(!obj->IsJSFunction());
@@ -87,7 +98,7 @@ void StartupSerializer::SerializeWeakReferencesAndDeferred() {
   // one entry with 'undefined' to terminate the partial snapshot cache.
   Object* undefined = isolate()->heap()->undefined_value();
   VisitRootPointer(Root::kPartialSnapshotCache, &undefined);
-  isolate()->heap()->IterateWeakRoots(this, VISIT_ALL);
+  isolate()->heap()->IterateWeakRoots(this, VISIT_ALL_FOR_STARTUP_SERIALIZATION);
   SerializeDeferredObjects();
   Pad();
 }
diff --git a/deps/v8/src/snapshot/startup-serializer.h b/deps/v8/src/snapshot/startup-serializer.h
index c17fba2fb4..4f0ae39368 100644
--- a/deps/v8/src/snapshot/startup-serializer.h
+++ b/deps/v8/src/snapshot/startup-serializer.h
@@ -6,6 +6,7 @@
 #define V8_SNAPSHOT_STARTUP_SERIALIZER_H_
 
 #include <bitset>
+#include <vector>
 #include "include/v8.h"
 #include "src/snapshot/serializer.h"
 
@@ -19,6 +20,9 @@ class StartupSerializer : public Serializer {
       v8::SnapshotCreator::FunctionCodeHandling function_code_handling);
   ~StartupSerializer() override;
 
+  static void IterateExternalStringTable(Isolate* isolate,
+              std::vector<Object*>* strings, RootVisitor* visitor);
+
   // Serialize the current state of the heap.  The order is:
   // 1) Immortal immovable roots
   // 2) Remaining strong references.