diff --git a/jerry-core/ecma/base/ecma-globals.h b/jerry-core/ecma/base/ecma-globals.h
index 72247db10..22ebd3276 100644
--- a/jerry-core/ecma/base/ecma-globals.h
+++ b/jerry-core/ecma/base/ecma-globals.h
@@ -400,6 +400,7 @@ typedef enum
   ECMA_PROPERTY_FLAG_WRITABLE = (1u << 2), /**< property is writable */
   ECMA_PROPERTY_FLAG_SINGLE_EXTERNAL = (1u << 2), /**< only one external pointer is assigned to this object */
   ECMA_PROPERTY_FLAG_DELETED = (1u << 3), /**< property is deleted */
+  ECMA_PROPERTY_FLAG_BUILT_IN = (1u << 3), /**< property is defined by the ECMAScript standard */
   ECMA_FAST_ARRAY_FLAG = (1u << 3), /**< array is fast array */
   ECMA_PROPERTY_FLAG_LCACHED = (1u << 4), /**< property is lcached */
 #if JERRY_ESNEXT
@@ -427,12 +428,48 @@ typedef enum
 #define ECMA_PROPERTY_CONFIGURABLE_WRITABLE \
   (ECMA_PROPERTY_FLAG_CONFIGURABLE | ECMA_PROPERTY_FLAG_WRITABLE)
 
+/**
+ * Property flag built-in.
+ */
+#define ECMA_PROPERTY_BUILT_IN_FIXED \
+  (ECMA_PROPERTY_FLAG_BUILT_IN)
+
 /**
  * Property flags enumerable, writable.
  */
 #define ECMA_PROPERTY_ENUMERABLE_WRITABLE \
   (ECMA_PROPERTY_FLAG_ENUMERABLE | ECMA_PROPERTY_FLAG_WRITABLE)
 
+/**
+ * Property flags built-in, configurable.
+ */
+#define ECMA_PROPERTY_BUILT_IN_CONFIGURABLE \
+  (ECMA_PROPERTY_FLAG_BUILT_IN | ECMA_PROPERTY_FLAG_CONFIGURABLE)
+
+/**
+ * Property flags built-in, configurable, enumerable.
+ */
+#define ECMA_PROPERTY_BUILT_IN_CONFIGURABLE_ENUMERABLE \
+  (ECMA_PROPERTY_FLAG_BUILT_IN | ECMA_PROPERTY_CONFIGURABLE_ENUMERABLE)
+
+/**
+ * Property flags built-in, configurable, writable.
+ */
+#define ECMA_PROPERTY_BUILT_IN_CONFIGURABLE_WRITABLE \
+  (ECMA_PROPERTY_FLAG_BUILT_IN | ECMA_PROPERTY_CONFIGURABLE_WRITABLE)
+
+/**
+ * Property flags built-in, writable.
+ */
+#define ECMA_PROPERTY_BUILT_IN_WRITABLE \
+  (ECMA_PROPERTY_FLAG_BUILT_IN | ECMA_PROPERTY_FLAG_WRITABLE)
+
+/**
+ * Property flags built-in, configurable, enumerable, writable.
+ */
+#define ECMA_PROPERTY_BUILT_IN_CONFIGURABLE_ENUMERABLE_WRITABLE \
+  (ECMA_PROPERTY_FLAG_BUILT_IN | ECMA_PROPERTY_CONFIGURABLE_ENUMERABLE_WRITABLE)
+
 /**
  * No attributes can be changed for this property.
  */
diff --git a/jerry-core/ecma/base/ecma-helpers.c b/jerry-core/ecma/base/ecma-helpers.c
index 70c759f24..151aaf4ef 100644
--- a/jerry-core/ecma/base/ecma-helpers.c
+++ b/jerry-core/ecma/base/ecma-helpers.c
@@ -582,7 +582,7 @@ ecma_create_named_data_property (ecma_object_t *object_p, /**< object */
   JERRY_ASSERT (ecma_is_lexical_environment (object_p)
                 || !ecma_op_object_is_fast_array (object_p));
   JERRY_ASSERT (ecma_find_named_property (object_p, name_p) == NULL);
-  JERRY_ASSERT ((prop_attributes & ~ECMA_PROPERTY_CONFIGURABLE_ENUMERABLE_WRITABLE) == 0);
+  JERRY_ASSERT ((prop_attributes & ~ECMA_PROPERTY_BUILT_IN_CONFIGURABLE_ENUMERABLE_WRITABLE) == 0);
 
   uint8_t type_and_flags = ECMA_PROPERTY_FLAG_DATA | prop_attributes;
 
@@ -610,7 +610,7 @@ ecma_create_named_accessor_property (ecma_object_t *object_p, /**< object */
   JERRY_ASSERT (ecma_is_lexical_environment (object_p)
                 || !ecma_op_object_is_fast_array (object_p));
   JERRY_ASSERT (ecma_find_named_property (object_p, name_p) == NULL);
-  JERRY_ASSERT ((prop_attributes & ~ECMA_PROPERTY_CONFIGURABLE_ENUMERABLE) == 0);
+  JERRY_ASSERT ((prop_attributes & ~ECMA_PROPERTY_BUILT_IN_CONFIGURABLE_ENUMERABLE) == 0);
 
   uint8_t type_and_flags = prop_attributes;
 
diff --git a/jerry-core/ecma/builtin-objects/ecma-builtin-internal-routines-template.inc.h b/jerry-core/ecma/builtin-objects/ecma-builtin-internal-routines-template.inc.h
index f49ff62ec..28bea6fc8 100644
--- a/jerry-core/ecma/builtin-objects/ecma-builtin-internal-routines-template.inc.h
+++ b/jerry-core/ecma/builtin-objects/ecma-builtin-internal-routines-template.inc.h
@@ -92,35 +92,35 @@ const ecma_builtin_property_descriptor_t PROPERTY_DESCRIPTOR_LIST_NAME[] =
   { \
     name, \
     ECMA_BUILTIN_PROPERTY_ROUTINE, \
-    ECMA_PROPERTY_CONFIGURABLE_WRITABLE, \
+    ECMA_PROPERTY_BUILT_IN_CONFIGURABLE_WRITABLE, \
     ECMA_ROUTINE_VALUE (ECMA_ROUTINE_ ## name ## c_function_name, length_prop_value) \
   },
 #define ROUTINE_CONFIGURABLE_ONLY(name, c_function_name, args_number, length_prop_value) \
   { \
     name, \
     ECMA_BUILTIN_PROPERTY_ROUTINE, \
-    ECMA_PROPERTY_FLAG_CONFIGURABLE, \
+    ECMA_PROPERTY_BUILT_IN_CONFIGURABLE, \
     ECMA_ROUTINE_VALUE (ECMA_ROUTINE_ ## name ## c_function_name, length_prop_value) \
   },
-#define ROUTINE_WITH_FLAGS(name, c_function_name, args_number, length_prop_value, flags) \
+#define ROUTINE_WITH_FLAGS(name, c_function_name, args_number, length_prop_value, prop_attributes) \
   { \
     name, \
     ECMA_BUILTIN_PROPERTY_ROUTINE, \
-    flags, \
+    (prop_attributes) | ECMA_PROPERTY_FLAG_BUILT_IN, \
     ECMA_ROUTINE_VALUE (ECMA_ROUTINE_ ## name ## c_function_name, length_prop_value) \
   },
 #define ACCESSOR_READ_ONLY(name, c_getter_func_name, prop_attributes) \
   { \
     name, \
     ECMA_BUILTIN_PROPERTY_ACCESSOR_READ_ONLY, \
-    prop_attributes, \
+    (prop_attributes) | ECMA_PROPERTY_FLAG_BUILT_IN, \
     ECMA_ACCESSOR_ ## name ## c_getter_func_name \
   },
 #define ACCESSOR_READ_WRITE(name, c_getter_func_name, c_setter_func_name, prop_attributes) \
   { \
     name, \
     ECMA_BUILTIN_PROPERTY_ACCESSOR_READ_WRITE, \
-    prop_attributes, \
+    (prop_attributes) | ECMA_PROPERTY_FLAG_BUILT_IN, \
     ECMA_ACCESSOR_READ_WRITE (ECMA_ACCESSOR_ ## name ## c_getter_func_name, \
                               ECMA_ACCESSOR_ ## name ## c_setter_func_name) \
   },
@@ -129,35 +129,35 @@ const ecma_builtin_property_descriptor_t PROPERTY_DESCRIPTOR_LIST_NAME[] =
   { \
     name, \
     ECMA_BUILTIN_PROPERTY_ROUTINE, \
-    ECMA_PROPERTY_CONFIGURABLE_WRITABLE, \
+    ECMA_PROPERTY_BUILT_IN_CONFIGURABLE_WRITABLE, \
     ECMA_ROUTINE_VALUE (c_function_name, length_prop_value) \
   },
 #define ROUTINE_CONFIGURABLE_ONLY(name, c_function_name, args_number, length_prop_value) \
   { \
     name, \
     ECMA_BUILTIN_PROPERTY_ROUTINE, \
-    ECMA_PROPERTY_FLAG_CONFIGURABLE, \
+    ECMA_PROPERTY_BUILT_IN_CONFIGURABLE, \
     ECMA_ROUTINE_VALUE (c_function_name, length_prop_value) \
   },
-#define ROUTINE_WITH_FLAGS(name, c_function_name, args_number, length_prop_value, flags) \
+#define ROUTINE_WITH_FLAGS(name, c_function_name, args_number, length_prop_value, prop_attributes) \
   { \
     name, \
     ECMA_BUILTIN_PROPERTY_ROUTINE, \
-    flags, \
+    (prop_attributes) | ECMA_PROPERTY_FLAG_BUILT_IN, \
     ECMA_ROUTINE_VALUE (c_function_name, length_prop_value) \
   },
 #define ACCESSOR_READ_ONLY(name, c_getter_func_name, prop_attributes) \
   { \
     name, \
     ECMA_BUILTIN_PROPERTY_ACCESSOR_READ_ONLY, \
-    prop_attributes, \
+    (prop_attributes) | ECMA_PROPERTY_FLAG_BUILT_IN, \
     c_getter_func_name \
   },
 #define ACCESSOR_READ_WRITE(name, c_getter_func_name, c_setter_func_name, prop_attributes) \
   { \
     name, \
     ECMA_BUILTIN_PROPERTY_ACCESSOR_READ_WRITE, \
-    prop_attributes, \
+    (prop_attributes) | ECMA_PROPERTY_FLAG_BUILT_IN, \
     ECMA_ACCESSOR_READ_WRITE (c_getter_func_name, c_setter_func_name) \
   },
 #endif /* !BUILTIN_CUSTOM_DISPATCH */
@@ -165,28 +165,28 @@ const ecma_builtin_property_descriptor_t PROPERTY_DESCRIPTOR_LIST_NAME[] =
   { \
     name, \
     ECMA_BUILTIN_PROPERTY_OBJECT, \
-    prop_attributes, \
+    (prop_attributes) | ECMA_PROPERTY_FLAG_BUILT_IN, \
     obj_builtin_id \
   },
 #define SIMPLE_VALUE(name, simple_value, prop_attributes) \
   { \
     name, \
     ECMA_BUILTIN_PROPERTY_SIMPLE, \
-    prop_attributes, \
+    (prop_attributes) | ECMA_PROPERTY_FLAG_BUILT_IN, \
     simple_value \
   },
 #define NUMBER_VALUE(name, number_value, prop_attributes) \
   { \
     name, \
     ECMA_BUILTIN_PROPERTY_NUMBER, \
-    prop_attributes, \
+    (prop_attributes) | ECMA_PROPERTY_FLAG_BUILT_IN, \
     number_value \
   },
 #define STRING_VALUE(name, magic_string_id, prop_attributes) \
   { \
     name, \
     ECMA_BUILTIN_PROPERTY_STRING, \
-    prop_attributes, \
+    (prop_attributes) | ECMA_PROPERTY_FLAG_BUILT_IN, \
     magic_string_id \
   },
 #if JERRY_ESNEXT
@@ -194,21 +194,21 @@ const ecma_builtin_property_descriptor_t PROPERTY_DESCRIPTOR_LIST_NAME[] =
   { \
     name, \
     ECMA_BUILTIN_PROPERTY_SYMBOL, \
-    ECMA_PROPERTY_FIXED, \
+    ECMA_PROPERTY_BUILT_IN_FIXED, \
     symbol \
   },
 #define INTRINSIC_PROPERTY(name, magic_string_id, prop_attributes) \
   { \
     name, \
     ECMA_BUILTIN_PROPERTY_INTRINSIC_PROPERTY, \
-    prop_attributes, \
+    (prop_attributes) | ECMA_PROPERTY_FLAG_BUILT_IN, \
     magic_string_id \
   },
 #define ACCESSOR_BUILTIN_FUNCTION(name, getter_builtin_id, setter_builtin_id, prop_attributes) \
   { \
     name, \
     ECMA_BUILTIN_PROPERTY_ACCESSOR_BUILTIN_FUNCTION, \
-    prop_attributes, \
+    (prop_attributes) | ECMA_PROPERTY_FLAG_BUILT_IN, \
     ECMA_ACCESSOR_READ_WRITE (getter_builtin_id, setter_builtin_id) \
   },
 #endif /* JERRY_ESNEXT */
diff --git a/jerry-core/ecma/builtin-objects/ecma-builtins.c b/jerry-core/ecma/builtin-objects/ecma-builtins.c
index 9724405a3..2210dca93 100644
--- a/jerry-core/ecma/builtin-objects/ecma-builtins.c
+++ b/jerry-core/ecma/builtin-objects/ecma-builtins.c
@@ -795,12 +795,10 @@ ecma_builtin_native_handler_try_to_instantiate_property (ecma_object_t *object_p
     {
       ecma_property_value_t *value_p = ecma_create_named_data_property (object_p,
                                                                         property_name_p,
-                                                                        ECMA_PROPERTY_FLAG_CONFIGURABLE,
+                                                                        ECMA_PROPERTY_BUILT_IN_CONFIGURABLE,
                                                                         &prop_p);
 
       value_p->value = ecma_make_magic_string_value (LIT_MAGIC_STRING__EMPTY);
-
-      ext_obj_p->u.built_in.u2.routine_flags |= ECMA_NATIVE_HANDLER_FLAGS_NAME_INITIALIZED;
     }
   }
   else if (ecma_compare_ecma_string_to_magic_id (property_name_p, LIT_MAGIC_STRING_LENGTH))
@@ -809,13 +807,11 @@ ecma_builtin_native_handler_try_to_instantiate_property (ecma_object_t *object_p
     {
       ecma_property_value_t *value_p = ecma_create_named_data_property (object_p,
                                                                         property_name_p,
-                                                                        ECMA_PROPERTY_FLAG_CONFIGURABLE,
+                                                                        ECMA_PROPERTY_BUILT_IN_CONFIGURABLE,
                                                                         &prop_p);
 
       const uint8_t length = ecma_builtin_handler_get_length (ext_obj_p->u.built_in.routine_id);
       value_p->value = ecma_make_integer_value (length);
-
-      ext_obj_p->u.built_in.u2.routine_flags |= ECMA_NATIVE_HANDLER_FLAGS_LENGTH_INITIALIZED;
     }
   }
 
@@ -835,22 +831,22 @@ ecma_builtin_native_handler_try_to_instantiate_property (ecma_object_t *object_p
  */
 ecma_property_t *
 ecma_builtin_routine_try_to_instantiate_property (ecma_object_t *object_p, /**< object */
-                                                  ecma_string_t *string_p) /**< property's name */
+                                                  ecma_string_t *property_name_p) /**< property name */
 {
   JERRY_ASSERT (ecma_get_object_is_builtin (object_p));
-  JERRY_ASSERT (ecma_get_object_type (object_p) == ECMA_OBJECT_TYPE_NATIVE_FUNCTION);
-  JERRY_ASSERT (ecma_builtin_function_is_routine (object_p));
+  JERRY_ASSERT (ecma_get_object_type (object_p) == ECMA_OBJECT_TYPE_NATIVE_FUNCTION
+                && ecma_builtin_function_is_routine (object_p));
 
   ecma_extended_object_t *ext_func_p = (ecma_extended_object_t *) object_p;
 
 #if JERRY_ESNEXT
   if (JERRY_UNLIKELY (ext_func_p->u.built_in.id == ECMA_BUILTIN_ID_HANDLER))
   {
-    return ecma_builtin_native_handler_try_to_instantiate_property (object_p, string_p);
+    return ecma_builtin_native_handler_try_to_instantiate_property (object_p, property_name_p);
   }
 #endif /* !JERRY_ESNEXT */
 
-  if (ecma_string_is_length (string_p))
+  if (ecma_string_is_length (property_name_p))
   {
     /*
      * Lazy instantiation of 'length' property
@@ -868,17 +864,16 @@ ecma_builtin_routine_try_to_instantiate_property (ecma_object_t *object_p, /**<
 
     /* We mark that the property was lazily instantiated,
      * as it is configurable and so can be deleted (ECMA-262 v6, 19.2.4.1) */
-    *bitset_p |= ECMA_BUILTIN_ROUTINE_LENGTH_INITIALIZED;
     ecma_property_value_t *len_prop_value_p = ecma_create_named_data_property (object_p,
-                                                                               string_p,
-                                                                               ECMA_PROPERTY_FLAG_CONFIGURABLE,
+                                                                               property_name_p,
+                                                                               ECMA_PROPERTY_BUILT_IN_CONFIGURABLE,
                                                                                &len_prop_p);
 #else /* !JERRY_ESNEXT */
     /* We don't need to mark that the property was already lazy instantiated,
      * as it is non-configurable and so can't be deleted (ECMA-262 v5, 13.2.5) */
     ecma_property_value_t *len_prop_value_p = ecma_create_named_data_property (object_p,
-                                                                               string_p,
-                                                                               ECMA_PROPERTY_FIXED,
+                                                                               property_name_p,
+                                                                               ECMA_PROPERTY_BUILT_IN_FIXED,
                                                                                &len_prop_p);
 #endif /* JERRY_ESNEXT */
 
@@ -908,7 +903,7 @@ ecma_builtin_routine_try_to_instantiate_property (ecma_object_t *object_p, /**<
   /*
    * Lazy instantiation of 'name' property
    */
-  if (ecma_compare_ecma_string_to_magic_id (string_p, LIT_MAGIC_STRING_NAME))
+  if (ecma_compare_ecma_string_to_magic_id (property_name_p, LIT_MAGIC_STRING_NAME))
   {
     uint8_t *bitset_p = &ext_func_p->u.built_in.u2.routine_flags;
 
@@ -919,11 +914,10 @@ ecma_builtin_routine_try_to_instantiate_property (ecma_object_t *object_p, /**<
     }
 
     /* We mark that the property was lazily instantiated */
-    *bitset_p |= ECMA_BUILTIN_ROUTINE_NAME_INITIALIZED;
     ecma_property_t *name_prop_p;
     ecma_property_value_t *name_prop_value_p = ecma_create_named_data_property (object_p,
-                                                                                string_p,
-                                                                                ECMA_PROPERTY_FLAG_CONFIGURABLE,
+                                                                                property_name_p,
+                                                                                ECMA_PROPERTY_BUILT_IN_CONFIGURABLE,
                                                                                 &name_prop_p);
 
     uint8_t routine_index = ext_func_p->u.built_in.u.routine_index;
@@ -995,18 +989,18 @@ ecma_builtin_routine_try_to_instantiate_property (ecma_object_t *object_p, /**<
  */
 ecma_property_t *
 ecma_builtin_try_to_instantiate_property (ecma_object_t *object_p, /**< object */
-                                          ecma_string_t *string_p) /**< property's name */
+                                          ecma_string_t *property_name_p) /**< property's name */
 {
   JERRY_ASSERT (ecma_get_object_is_builtin (object_p));
 
-  lit_magic_string_id_t magic_string_id = ecma_get_string_magic (string_p);
+  lit_magic_string_id_t magic_string_id = ecma_get_string_magic (property_name_p);
 
 #if JERRY_ESNEXT
-  if (JERRY_UNLIKELY (ecma_prop_name_is_symbol (string_p)))
+  if (JERRY_UNLIKELY (ecma_prop_name_is_symbol (property_name_p)))
   {
-    if (string_p->u.hash & ECMA_GLOBAL_SYMBOL_FLAG)
+    if (property_name_p->u.hash & ECMA_GLOBAL_SYMBOL_FLAG)
     {
-      magic_string_id = (string_p->u.hash >> ECMA_GLOBAL_SYMBOL_SHIFT);
+      magic_string_id = (property_name_p->u.hash >> ECMA_GLOBAL_SYMBOL_SHIFT);
     }
   }
 #endif /* JERRY_ESNEXT */
@@ -1034,7 +1028,6 @@ ecma_builtin_try_to_instantiate_property (ecma_object_t *object_p, /**< object *
   JERRY_ASSERT (builtin_id < ECMA_BUILTIN_ID__COUNT);
 
   const ecma_builtin_property_descriptor_t *property_list_p = ecma_builtin_property_list_references[builtin_id];
-
   const ecma_builtin_property_descriptor_t *curr_property_p = property_list_p;
 
   while (curr_property_p->magic_string_id != magic_string_id)
@@ -1064,8 +1057,6 @@ ecma_builtin_try_to_instantiate_property (ecma_object_t *object_p, /**< object *
     return NULL;
   }
 
-  *bitset_p |= bit_for_index;
-
   ecma_value_t value = ECMA_VALUE_EMPTY;
   bool is_accessor = false;
   ecma_object_t *getter_p = NULL;
@@ -1217,10 +1208,12 @@ ecma_builtin_try_to_instantiate_property (ecma_object_t *object_p, /**< object *
 
   ecma_property_t *prop_p;
 
+  JERRY_ASSERT (curr_property_p->attributes & ECMA_PROPERTY_FLAG_BUILT_IN);
+
   if (is_accessor)
   {
     ecma_create_named_accessor_property (object_p,
-                                         string_p,
+                                         property_name_p,
                                          getter_p,
                                          setter_p,
                                          curr_property_p->attributes,
@@ -1238,7 +1231,7 @@ ecma_builtin_try_to_instantiate_property (ecma_object_t *object_p, /**< object *
   else
   {
     ecma_property_value_t *prop_value_p = ecma_create_named_data_property (object_p,
-                                                                           string_p,
+                                                                           property_name_p,
                                                                            curr_property_p->attributes,
                                                                            &prop_p);
     prop_value_p->value = value;
@@ -1252,6 +1245,133 @@ ecma_builtin_try_to_instantiate_property (ecma_object_t *object_p, /**< object *
 
 #if JERRY_ESNEXT
 
+/**
+ * Delete configurable properties of native handlers.
+ */
+static void
+ecma_builtin_native_handler_delete_built_in_property (ecma_object_t *object_p, /**< object */
+                                                      ecma_string_t *property_name_p) /**< property name */
+{
+  ecma_extended_object_t *extended_obj_p = (ecma_extended_object_t *) object_p;
+
+  if (ecma_compare_ecma_string_to_magic_id (property_name_p, LIT_MAGIC_STRING_LENGTH))
+  {
+    JERRY_ASSERT (!(extended_obj_p->u.built_in.u2.routine_flags & ECMA_NATIVE_HANDLER_FLAGS_LENGTH_INITIALIZED));
+
+    extended_obj_p->u.built_in.u2.routine_flags |= ECMA_NATIVE_HANDLER_FLAGS_LENGTH_INITIALIZED;
+    return;
+  }
+
+  JERRY_ASSERT (ecma_compare_ecma_string_to_magic_id (property_name_p, LIT_MAGIC_STRING_NAME));
+  JERRY_ASSERT (!(extended_obj_p->u.built_in.u2.routine_flags & ECMA_NATIVE_HANDLER_FLAGS_NAME_INITIALIZED));
+
+  extended_obj_p->u.built_in.u2.routine_flags |= ECMA_NATIVE_HANDLER_FLAGS_NAME_INITIALIZED;
+} /* ecma_builtin_native_handler_delete_built_in_property */
+
+/**
+ * Delete configurable properties of built-in routines.
+ */
+void
+ecma_builtin_routine_delete_built_in_property (ecma_object_t *object_p, /**< object */
+                                               ecma_string_t *property_name_p) /**< property name */
+{
+  JERRY_ASSERT (ecma_get_object_is_builtin (object_p));
+  JERRY_ASSERT (ecma_get_object_type (object_p) == ECMA_OBJECT_TYPE_NATIVE_FUNCTION
+                && ecma_builtin_function_is_routine (object_p));
+
+  ecma_extended_object_t *extended_obj_p = (ecma_extended_object_t *) object_p;
+
+  if (JERRY_UNLIKELY (extended_obj_p->u.built_in.id == ECMA_BUILTIN_ID_HANDLER))
+  {
+    ecma_builtin_native_handler_delete_built_in_property (object_p, property_name_p);
+    return;
+  }
+
+  uint8_t *bitset_p = &extended_obj_p->u.built_in.u2.routine_flags;
+
+  if (ecma_compare_ecma_string_to_magic_id (property_name_p, LIT_MAGIC_STRING_LENGTH))
+  {
+    JERRY_ASSERT (!(*bitset_p & ECMA_BUILTIN_ROUTINE_LENGTH_INITIALIZED));
+
+    *bitset_p |= ECMA_BUILTIN_ROUTINE_LENGTH_INITIALIZED;
+    return;
+  }
+
+  JERRY_ASSERT (ecma_compare_ecma_string_to_magic_id (property_name_p, LIT_MAGIC_STRING_NAME));
+  JERRY_ASSERT (!(*bitset_p & ECMA_BUILTIN_ROUTINE_NAME_INITIALIZED));
+
+  *bitset_p |= ECMA_BUILTIN_ROUTINE_NAME_INITIALIZED;
+} /* ecma_builtin_routine_delete_built_in_property */
+
+#endif /* JERRY_ESNEXT */
+
+/**
+ * Delete configurable properties of built-ins.
+ */
+void
+ecma_builtin_delete_built_in_property (ecma_object_t *object_p, /**< object */
+                                       ecma_string_t *property_name_p) /**< property name */
+{
+  JERRY_ASSERT (ecma_get_object_is_builtin (object_p));
+  JERRY_ASSERT (ecma_get_object_type (object_p) != ECMA_OBJECT_TYPE_NATIVE_FUNCTION
+                || !ecma_builtin_function_is_routine (object_p));
+
+  lit_magic_string_id_t magic_string_id = ecma_get_string_magic (property_name_p);
+
+#if JERRY_ESNEXT
+  if (JERRY_UNLIKELY (ecma_prop_name_is_symbol (property_name_p)))
+  {
+    if (property_name_p->u.hash & ECMA_GLOBAL_SYMBOL_FLAG)
+    {
+      magic_string_id = (property_name_p->u.hash >> ECMA_GLOBAL_SYMBOL_SHIFT);
+    }
+  }
+#endif /* JERRY_ESNEXT */
+
+  ecma_built_in_props_t *built_in_props_p;
+  ecma_object_type_t object_type = ecma_get_object_type (object_p);
+  JERRY_ASSERT (object_type != ECMA_OBJECT_TYPE_FUNCTION || !ecma_builtin_function_is_routine (object_p));
+
+  if (ECMA_BUILTIN_IS_EXTENDED_BUILT_IN (object_type))
+  {
+    built_in_props_p = &((ecma_extended_built_in_object_t *) object_p)->built_in;
+  }
+  else
+  {
+    built_in_props_p = &((ecma_extended_object_t *) object_p)->u.built_in;
+  }
+
+  ecma_builtin_id_t builtin_id = (ecma_builtin_id_t) built_in_props_p->id;
+
+  JERRY_ASSERT (builtin_id < ECMA_BUILTIN_ID__COUNT);
+
+  const ecma_builtin_property_descriptor_t *property_list_p = ecma_builtin_property_list_references[builtin_id];
+  const ecma_builtin_property_descriptor_t *curr_property_p = property_list_p;
+
+  while (curr_property_p->magic_string_id != magic_string_id)
+  {
+    JERRY_ASSERT (curr_property_p->magic_string_id != LIT_MAGIC_STRING__COUNT);
+    curr_property_p++;
+  }
+
+  uint32_t index = (uint32_t) (curr_property_p - property_list_p);
+  uint8_t *bitset_p = built_in_props_p->u2.instantiated_bitset + (index >> 3);
+
+#if JERRY_BUILTIN_REALMS
+  if (index >= 8 * sizeof (uint8_t))
+  {
+    bitset_p += sizeof (ecma_value_t);
+  }
+#endif /* JERRY_BUILTIN_REALMS */
+
+  uint8_t bit_for_index = (uint8_t) (1u << (index & 0x7));
+  JERRY_ASSERT (!(*bitset_p & bit_for_index));
+
+  *bitset_p |= bit_for_index;
+} /* ecma_builtin_delete_built_in_property */
+
+#if JERRY_ESNEXT
+
 /**
  * List names of an Built-in native handler object's lazy instantiated properties,
  * adding them to corresponding string collections
@@ -1292,8 +1412,8 @@ ecma_builtin_routine_list_lazy_property_names (ecma_object_t *object_p, /**< a b
                                                ecma_property_counter_t *prop_counter_p)  /**< prop counter */
 {
   JERRY_ASSERT (ecma_get_object_is_builtin (object_p));
-  JERRY_ASSERT (ecma_get_object_type (object_p) == ECMA_OBJECT_TYPE_NATIVE_FUNCTION);
-  JERRY_ASSERT (ecma_builtin_function_is_routine (object_p));
+  JERRY_ASSERT (ecma_get_object_type (object_p) == ECMA_OBJECT_TYPE_NATIVE_FUNCTION
+                && ecma_builtin_function_is_routine (object_p));
 
 #if JERRY_ESNEXT
   ecma_extended_object_t *ext_func_p = (ecma_extended_object_t *) object_p;
@@ -1382,7 +1502,7 @@ ecma_builtin_list_lazy_property_names (ecma_object_t *object_p, /**< a built-in
       {
         ecma_string_t *name_p = ecma_op_get_global_symbol (curr_property_p->magic_string_id);
 
-        if (!(bitset & bit_for_index) || ecma_op_ordinary_object_has_own_property (object_p, name_p))
+        if (!(bitset & bit_for_index))
         {
           ecma_value_t name = ecma_make_symbol_value (name_p);
           ecma_collection_push_back (prop_names_p, name);
@@ -1395,16 +1515,11 @@ ecma_builtin_list_lazy_property_names (ecma_object_t *object_p, /**< a built-in
       }
 #endif /* JERRY_ESNEXT */
     }
-    else
+    else if (!(bitset & bit_for_index))
     {
-      ecma_string_t *name_p = ecma_get_magic_string ((lit_magic_string_id_t) curr_property_p->magic_string_id);
-
-      if (!(bitset & bit_for_index) || ecma_op_ordinary_object_has_own_property (object_p, name_p))
-      {
-        ecma_value_t name = ecma_make_magic_string_value ((lit_magic_string_id_t) curr_property_p->magic_string_id);
-        ecma_collection_push_back (prop_names_p, name);
-        prop_counter_p->string_named_props++;
-      }
+      ecma_value_t name = ecma_make_magic_string_value ((lit_magic_string_id_t) curr_property_p->magic_string_id);
+      ecma_collection_push_back (prop_names_p, name);
+      prop_counter_p->string_named_props++;
     }
 
     curr_property_p++;
diff --git a/jerry-core/ecma/builtin-objects/ecma-builtins.h b/jerry-core/ecma/builtin-objects/ecma-builtins.h
index e8a2260c6..2a50e5df0 100644
--- a/jerry-core/ecma/builtin-objects/ecma-builtins.h
+++ b/jerry-core/ecma/builtin-objects/ecma-builtins.h
@@ -128,9 +128,15 @@ ecma_value_t
 ecma_builtin_dispatch_construct (ecma_object_t *obj_p, const ecma_value_t *arguments_list_p,
                                  uint32_t arguments_list_len);
 ecma_property_t *
-ecma_builtin_routine_try_to_instantiate_property (ecma_object_t *object_p, ecma_string_t *string_p);
+ecma_builtin_routine_try_to_instantiate_property (ecma_object_t *object_p, ecma_string_t *property_name_p);
 ecma_property_t *
-ecma_builtin_try_to_instantiate_property (ecma_object_t *object_p, ecma_string_t *string_p);
+ecma_builtin_try_to_instantiate_property (ecma_object_t *object_p, ecma_string_t *property_name_p);
+#if JERRY_ESNEXT
+void
+ecma_builtin_routine_delete_built_in_property (ecma_object_t *object_p, ecma_string_t *property_name_p);
+#endif /* JERRY_ESNEXT */
+void
+ecma_builtin_delete_built_in_property (ecma_object_t *object_p, ecma_string_t *property_name_p);
 void
 ecma_builtin_routine_list_lazy_property_names (ecma_object_t *object_p,
                                                ecma_collection_t *prop_names_p,
diff --git a/jerry-core/ecma/operations/ecma-array-object.c b/jerry-core/ecma/operations/ecma-array-object.c
index 900e8d977..ca64871ab 100644
--- a/jerry-core/ecma/operations/ecma-array-object.c
+++ b/jerry-core/ecma/operations/ecma-array-object.c
@@ -501,19 +501,20 @@ ecma_fast_array_extend (ecma_object_t *object_p, /**< fast access mode array obj
  * Delete the array object's property referenced by its value pointer.
  *
  * Note: specified property must be owned by specified object.
+ *
+ * @return true, if the property is deleted
+ *         false, otherwise
  */
-void
+bool
 ecma_array_object_delete_property (ecma_object_t *object_p, /**< object */
-                                   ecma_string_t *property_name_p, /**< property name */
-                                   ecma_property_value_t *prop_value_p) /**< property value reference */
+                                   ecma_string_t *property_name_p) /**< property name */
 {
   JERRY_ASSERT (ecma_get_object_type (object_p) == ECMA_OBJECT_TYPE_ARRAY);
   ecma_extended_object_t *ext_obj_p = (ecma_extended_object_t *) object_p;
 
   if (!ecma_op_object_is_fast_array (object_p))
   {
-    ecma_delete_property (object_p, prop_value_p);
-    return;
+    return false;
   }
 
   JERRY_ASSERT (object_p->u1.property_list_cp != JMEM_CP_NULL);
@@ -527,13 +528,14 @@ ecma_array_object_delete_property (ecma_object_t *object_p, /**< object */
 
   if (ecma_is_value_array_hole (values_p[index]))
   {
-    return;
+    return true;
   }
 
   ecma_free_value_if_not_object (values_p[index]);
 
   values_p[index] = ECMA_VALUE_ARRAY_HOLE;
   ext_obj_p->u.array.length_prop_and_hole_count += ECMA_FAST_ARRAY_HOLE_ONE;
+  return true;
 } /* ecma_array_object_delete_property */
 
 /**
diff --git a/jerry-core/ecma/operations/ecma-array-object.h b/jerry-core/ecma/operations/ecma-array-object.h
index 831cfe68a..2e6e8fe4e 100644
--- a/jerry-core/ecma/operations/ecma-array-object.h
+++ b/jerry-core/ecma/operations/ecma-array-object.h
@@ -89,9 +89,8 @@ ecma_fast_array_extend (ecma_object_t *object_p, uint32_t new_lengt);
 bool
 ecma_fast_array_set_property (ecma_object_t *object_p, uint32_t index, ecma_value_t value);
 
-void
-ecma_array_object_delete_property (ecma_object_t *object_p, ecma_string_t *property_name_p,
-                                   ecma_property_value_t *prop_value_p);
+bool
+ecma_array_object_delete_property (ecma_object_t *object_p, ecma_string_t *property_name_p);
 
 uint32_t
 ecma_delete_fast_array_properties (ecma_object_t *object_p, uint32_t new_length);
diff --git a/jerry-core/ecma/operations/ecma-function-object.c b/jerry-core/ecma/operations/ecma-function-object.c
index 0034286d2..3f12dc1cf 100644
--- a/jerry-core/ecma/operations/ecma-function-object.c
+++ b/jerry-core/ecma/operations/ecma-function-object.c
@@ -1702,7 +1702,7 @@ ecma_op_lazy_instantiate_prototype_object (ecma_object_t *object_p) /**< the fun
   ecma_property_value_t *prototype_prop_value_p;
   prototype_prop_value_p = ecma_create_named_data_property (object_p,
                                                             ecma_get_magic_string (LIT_MAGIC_STRING_PROTOTYPE),
-                                                            ECMA_PROPERTY_FLAG_WRITABLE,
+                                                            ECMA_PROPERTY_BUILT_IN_WRITABLE,
                                                             &prototype_prop_p);
 
   prototype_prop_value_p->value = ecma_make_object_value (proto_object_p);
@@ -1734,73 +1734,72 @@ ecma_op_function_try_to_lazy_instantiate_property (ecma_object_t *object_p, /**<
   {
     ecma_extended_object_t *ext_func_p = (ecma_extended_object_t *) object_p;
 
-    if (!ECMA_GET_FIRST_BIT_FROM_POINTER_TAG (ext_func_p->u.function.scope_cp))
+    if (ECMA_GET_FIRST_BIT_FROM_POINTER_TAG (ext_func_p->u.function.scope_cp))
     {
-      /* Initialize 'length' property */
-      const ecma_compiled_code_t *bytecode_data_p = ecma_op_function_get_compiled_code (ext_func_p);
-      uint32_t len;
-
-      if (bytecode_data_p->status_flags & CBC_CODE_FLAGS_UINT16_ARGUMENTS)
-      {
-        cbc_uint16_arguments_t *args_p = (cbc_uint16_arguments_t *) bytecode_data_p;
-        len = args_p->argument_end;
-      }
-      else
-      {
-        cbc_uint8_arguments_t *args_p = (cbc_uint8_arguments_t *) bytecode_data_p;
-        len = args_p->argument_end;
-      }
-
-      if (bytecode_data_p->status_flags & CBC_CODE_FLAGS_HAS_EXTENDED_INFO)
-      {
-        uint8_t *extended_info_p = ecma_compiled_code_resolve_extended_info (bytecode_data_p);
-
-        if (*extended_info_p & CBC_EXTENDED_CODE_FLAGS_HAS_ARGUMENT_LENGTH)
-        {
-          len = ecma_extended_info_decode_vlq (&extended_info_p);
-        }
-      }
-
-      /* Set tag bit to represent initialized 'length' property */
-      ECMA_SET_FIRST_BIT_TO_POINTER_TAG (ext_func_p->u.function.scope_cp);
-      ecma_property_t *value_prop_p;
-      ecma_property_value_t *value_p = ecma_create_named_data_property (object_p,
-                                                                        property_name_p,
-                                                                        ECMA_PROPERTY_FLAG_CONFIGURABLE,
-                                                                        &value_prop_p);
-      value_p->value = ecma_make_uint32_value (len);
-      return value_prop_p;
+      return NULL;
     }
 
-    return NULL;
+    /* Initialize 'length' property */
+    const ecma_compiled_code_t *bytecode_data_p = ecma_op_function_get_compiled_code (ext_func_p);
+    uint32_t len;
+
+    if (bytecode_data_p->status_flags & CBC_CODE_FLAGS_UINT16_ARGUMENTS)
+    {
+      cbc_uint16_arguments_t *args_p = (cbc_uint16_arguments_t *) bytecode_data_p;
+      len = args_p->argument_end;
+    }
+    else
+    {
+      cbc_uint8_arguments_t *args_p = (cbc_uint8_arguments_t *) bytecode_data_p;
+      len = args_p->argument_end;
+    }
+
+    if (bytecode_data_p->status_flags & CBC_CODE_FLAGS_HAS_EXTENDED_INFO)
+    {
+      uint8_t *extended_info_p = ecma_compiled_code_resolve_extended_info (bytecode_data_p);
+
+      if (*extended_info_p & CBC_EXTENDED_CODE_FLAGS_HAS_ARGUMENT_LENGTH)
+      {
+        len = ecma_extended_info_decode_vlq (&extended_info_p);
+      }
+    }
+
+    ecma_property_t *value_prop_p;
+    ecma_property_value_t *value_p = ecma_create_named_data_property (object_p,
+                                                                      property_name_p,
+                                                                      ECMA_PROPERTY_BUILT_IN_CONFIGURABLE,
+                                                                      &value_prop_p);
+    value_p->value = ecma_make_uint32_value (len);
+    return value_prop_p;
   }
 
   if (ecma_compare_ecma_string_to_magic_id (property_name_p, LIT_MAGIC_STRING_NAME))
   {
     ecma_extended_object_t *ext_func_p = (ecma_extended_object_t *) object_p;
-    if (!ECMA_GET_SECOND_BIT_FROM_POINTER_TAG (ext_func_p->u.function.scope_cp))
+
+    if (ECMA_GET_SECOND_BIT_FROM_POINTER_TAG (ext_func_p->u.function.scope_cp))
     {
-      /* Set tag bit to represent initialized 'name' property */
-      ECMA_SET_SECOND_BIT_TO_POINTER_TAG (ext_func_p->u.function.scope_cp);
-      const ecma_compiled_code_t *bytecode_data_p = ecma_op_function_get_compiled_code (ext_func_p);
-
-      if (CBC_FUNCTION_GET_TYPE (bytecode_data_p->status_flags) != CBC_FUNCTION_CONSTRUCTOR)
-      {
-        ecma_value_t value = *ecma_compiled_code_resolve_function_name (bytecode_data_p);
-        JERRY_ASSERT (ecma_is_value_string (value));
-
-        /* Initialize 'name' property */
-        ecma_property_t *value_prop_p;
-        ecma_property_value_t *value_p = ecma_create_named_data_property (object_p,
-                                                                          property_name_p,
-                                                                          ECMA_PROPERTY_FLAG_CONFIGURABLE,
-                                                                          &value_prop_p);
-        value_p->value = ecma_copy_value (value);
-        return value_prop_p;
-      }
+      return NULL;
     }
 
-    return NULL;
+    const ecma_compiled_code_t *bytecode_data_p = ecma_op_function_get_compiled_code (ext_func_p);
+
+    if (CBC_FUNCTION_GET_TYPE (bytecode_data_p->status_flags) == CBC_FUNCTION_CONSTRUCTOR)
+    {
+      return NULL;
+    }
+
+    ecma_value_t value = *ecma_compiled_code_resolve_function_name (bytecode_data_p);
+    JERRY_ASSERT (ecma_is_value_string (value));
+
+    /* Initialize 'name' property */
+    ecma_property_t *value_prop_p;
+    ecma_property_value_t *value_p = ecma_create_named_data_property (object_p,
+                                                                      property_name_p,
+                                                                      ECMA_PROPERTY_BUILT_IN_CONFIGURABLE,
+                                                                      &value_prop_p);
+    value_p->value = ecma_copy_value (value);
+    return value_prop_p;
   }
 #endif /* JERRY_ESNEXT */
 
@@ -1826,7 +1825,7 @@ ecma_op_function_try_to_lazy_instantiate_property (ecma_object_t *object_p, /**<
       /* The property_name_p argument contains the name. */
       ecma_property_value_t *value_p = ecma_create_named_data_property (object_p,
                                                                         property_name_p,
-                                                                        ECMA_PROPERTY_FIXED,
+                                                                        ECMA_PROPERTY_BUILT_IN_FIXED,
                                                                         &value_prop_p);
       value_p->value = is_arguments ? ECMA_VALUE_NULL : ECMA_VALUE_UNDEFINED;
       return value_prop_p;
@@ -1842,7 +1841,7 @@ ecma_op_function_try_to_lazy_instantiate_property (ecma_object_t *object_p, /**<
                                            property_name_p,
                                            thrower_p,
                                            thrower_p,
-                                           ECMA_PROPERTY_FIXED,
+                                           ECMA_PROPERTY_BUILT_IN_FIXED,
                                            &caller_prop_p);
       return caller_prop_p;
     }
@@ -1909,13 +1908,10 @@ ecma_op_bound_function_try_to_lazy_instantiate_property (ecma_object_t *object_p
       return NULL;
     }
 
-    length_attributes = ECMA_PROPERTY_FLAG_CONFIGURABLE;
+    length_attributes = ECMA_PROPERTY_BUILT_IN_CONFIGURABLE;
     length = ecma_get_number_from_value (bound_func_p->target_length) - (args_length - 1);
-
-    /* Set tag bit to represent initialized 'length' property */
-    ECMA_SET_FIRST_BIT_TO_POINTER_TAG (bound_func_p->header.u.bound_function.target_function);
 #else /* !JERRY_ESNEXT */
-    length_attributes = ECMA_PROPERTY_FIXED;
+    length_attributes = ECMA_PROPERTY_BUILT_IN_FIXED;
 
     ecma_object_t *target_func_p;
     target_func_p = ECMA_GET_NON_NULL_POINTER_FROM_POINTER_TAG (ecma_object_t,
@@ -1960,7 +1956,7 @@ ecma_op_bound_function_try_to_lazy_instantiate_property (ecma_object_t *object_p
                                          property_name_p,
                                          thrower_p,
                                          thrower_p,
-                                         ECMA_PROPERTY_FIXED,
+                                         ECMA_PROPERTY_BUILT_IN_FIXED,
                                          &caller_prop_p);
     return caller_prop_p;
   }
@@ -1969,6 +1965,49 @@ ecma_op_bound_function_try_to_lazy_instantiate_property (ecma_object_t *object_p
   return NULL;
 } /* ecma_op_bound_function_try_to_lazy_instantiate_property */
 
+#if JERRY_ESNEXT
+
+/**
+ * Delete configurable properties of functions.
+ */
+void
+ecma_op_function_delete_built_in_property (ecma_object_t *object_p, /**< object */
+                                           ecma_string_t *property_name_p) /**< property name */
+{
+  ecma_extended_object_t *ext_func_p = (ecma_extended_object_t *) object_p;
+
+  if (ecma_compare_ecma_string_to_magic_id (property_name_p, LIT_MAGIC_STRING_LENGTH))
+  {
+    JERRY_ASSERT (!ECMA_GET_FIRST_BIT_FROM_POINTER_TAG (ext_func_p->u.function.scope_cp));
+    ECMA_SET_FIRST_BIT_TO_POINTER_TAG (ext_func_p->u.function.scope_cp);
+    return;
+  }
+
+  JERRY_ASSERT (ecma_compare_ecma_string_to_magic_id (property_name_p, LIT_MAGIC_STRING_NAME));
+  JERRY_ASSERT (!ECMA_GET_SECOND_BIT_FROM_POINTER_TAG (ext_func_p->u.function.scope_cp));
+
+  ECMA_SET_SECOND_BIT_TO_POINTER_TAG (ext_func_p->u.function.scope_cp);
+} /* ecma_op_function_delete_built_in_property */
+
+/**
+ * Delete configurable properties of bound functions.
+ */
+void
+ecma_op_bound_function_delete_built_in_property (ecma_object_t *object_p, /**< object */
+                                                 ecma_string_t *property_name_p) /**< property name */
+{
+  JERRY_UNUSED (property_name_p);
+
+  ecma_bound_function_t *bound_func_p = (ecma_bound_function_t *) object_p;
+
+  JERRY_ASSERT (ecma_compare_ecma_string_to_magic_id (property_name_p, LIT_MAGIC_STRING_LENGTH));
+  JERRY_ASSERT (!ECMA_GET_FIRST_BIT_FROM_POINTER_TAG (bound_func_p->header.u.bound_function.target_function));
+
+  ECMA_SET_FIRST_BIT_TO_POINTER_TAG (bound_func_p->header.u.bound_function.target_function);
+} /* ecma_op_bound_function_delete_built_in_property */
+
+#endif /* JERRY_ESNEXT */
+
 /**
  * List names of a Function object's lazy instantiated properties,
  * adding them to corresponding string collections
@@ -2058,7 +2097,10 @@ ecma_op_external_function_list_lazy_property_names (ecma_object_t *object_p, /**
 #if !JERRY_ESNEXT
   JERRY_UNUSED (object_p);
 #else /* JERRY_ESNEXT */
-  if (!ecma_op_ordinary_object_has_own_property (object_p, ecma_get_magic_string (LIT_MAGIC_STRING_PROTOTYPE)))
+  /* TODO: implicit class constructors need rework, and this code should be updated afterwards. */
+  ecma_property_t *property_p = ecma_find_named_property (object_p, ecma_get_magic_string (LIT_MAGIC_STRING_PROTOTYPE));
+
+  if (property_p == NULL || (*property_p & ECMA_PROPERTY_FLAG_BUILT_IN))
 #endif /* !JERRY_ESNEXT */
   {
     /* 'prototype' property is non-enumerable (ECMA-262 v5, 13.2.18) */
diff --git a/jerry-core/ecma/operations/ecma-function-object.h b/jerry-core/ecma/operations/ecma-function-object.h
index 19e2a422d..44b1963bb 100644
--- a/jerry-core/ecma/operations/ecma-function-object.h
+++ b/jerry-core/ecma/operations/ecma-function-object.h
@@ -108,6 +108,14 @@ ecma_op_external_function_try_to_lazy_instantiate_property (ecma_object_t *objec
 ecma_property_t *
 ecma_op_bound_function_try_to_lazy_instantiate_property (ecma_object_t *object_p, ecma_string_t *property_name_p);
 
+#if JERRY_ESNEXT
+void
+ecma_op_function_delete_built_in_property (ecma_object_t *object_p, ecma_string_t *property_name_p);
+
+void
+ecma_op_bound_function_delete_built_in_property (ecma_object_t *object_p, ecma_string_t *property_name_p);
+#endif /* JERRY_ESNEXT */
+
 void
 ecma_op_function_list_lazy_property_names (ecma_object_t *object_p,
                                            ecma_collection_t *prop_names_p,
diff --git a/jerry-core/ecma/operations/ecma-objects-general.c b/jerry-core/ecma/operations/ecma-objects-general.c
index 78c1ddffa..8519960ee 100644
--- a/jerry-core/ecma/operations/ecma-objects-general.c
+++ b/jerry-core/ecma/operations/ecma-objects-general.c
@@ -107,30 +107,72 @@ ecma_op_general_object_delete (ecma_object_t *obj_p, /**< the object */
   }
 
   /* 3. */
-  if (ecma_is_property_configurable (property))
+  if (!ecma_is_property_configurable (property))
   {
-    if (ecma_get_object_type (obj_p) == ECMA_OBJECT_TYPE_ARRAY)
+    /* 4. */
+    if (is_throw)
     {
-      ecma_array_object_delete_property (obj_p, property_name_p, property_ref.value_p);
-    }
-    else
-    {
-      /* a. */
-      ecma_delete_property (obj_p, property_ref.value_p);
+      return ecma_raise_type_error (ECMA_ERR_MSG ("Expected a configurable property"));
     }
 
-    /* b. */
+    /* 5. */
+    return ECMA_VALUE_FALSE;
+  }
+
+  ecma_object_type_t type = ecma_get_object_type (obj_p);
+
+  if (type == ECMA_OBJECT_TYPE_ARRAY
+      && ecma_array_object_delete_property (obj_p, property_name_p))
+  {
     return ECMA_VALUE_TRUE;
   }
 
-  /* 4. */
-  if (is_throw)
+  /* a. */
+  ecma_delete_property (obj_p, property_ref.value_p);
+
+  if (property & ECMA_PROPERTY_FLAG_BUILT_IN)
   {
-    return ecma_raise_type_error (ECMA_ERR_MSG ("Expected a configurable property"));
+#if JERRY_ESNEXT
+    if (ecma_get_object_is_builtin (obj_p))
+    {
+      if (type == ECMA_OBJECT_TYPE_NATIVE_FUNCTION && ecma_builtin_function_is_routine (obj_p))
+      {
+        ecma_builtin_routine_delete_built_in_property (obj_p, property_name_p);
+      }
+      else
+      {
+        ecma_builtin_delete_built_in_property (obj_p, property_name_p);
+      }
+    }
+    else
+    {
+      switch (type)
+      {
+        case ECMA_OBJECT_TYPE_FUNCTION:
+        {
+          ecma_op_function_delete_built_in_property (obj_p, property_name_p);
+          break;
+        }
+        case ECMA_OBJECT_TYPE_BOUND_FUNCTION:
+        {
+          ecma_op_bound_function_delete_built_in_property (obj_p, property_name_p);
+          break;
+        }
+        default:
+        {
+          break;
+        }
+      }
+    }
+#else /* !JERRY_ESNEXT */
+    JERRY_ASSERT (ecma_get_object_is_builtin (obj_p));
+
+    ecma_builtin_delete_built_in_property (obj_p, property_name_p);
+#endif /* JERRY_ESNEXT */
   }
 
-  /* 5. */
-  return ECMA_VALUE_FALSE;
+  /* b. */
+  return ECMA_VALUE_TRUE;
 } /* ecma_op_general_object_delete */
 
 /**
diff --git a/jerry-core/ecma/operations/ecma-objects.c b/jerry-core/ecma/operations/ecma-objects.c
index 81ae13568..4696c72c6 100644
--- a/jerry-core/ecma/operations/ecma-objects.c
+++ b/jerry-core/ecma/operations/ecma-objects.c
@@ -2551,7 +2551,8 @@ ecma_op_object_own_property_keys (ecma_object_t *obj_p) /**< object */
     {
       ecma_property_t *property_p = prop_iter_p->types + i;
 
-      if (ECMA_PROPERTY_IS_RAW (*property_p))
+      if (ECMA_PROPERTY_IS_RAW (*property_p)
+          && !(*property_p & ECMA_PROPERTY_FLAG_BUILT_IN))
       {
         ecma_property_pair_t *prop_pair_p = (ecma_property_pair_t *) prop_iter_p;
 
diff --git a/tests/jerry/es.next/regression-test-issue-3267.js b/tests/jerry/es.next/regression-test-issue-3267.js
index 43f9831d3..c4a6d8246 100644
--- a/tests/jerry/es.next/regression-test-issue-3267.js
+++ b/tests/jerry/es.next/regression-test-issue-3267.js
@@ -18,6 +18,5 @@ assert (Object.isSealed(hasProp) === false);
 
 var keys = Object.getOwnPropertyNames(hasProp);
 assert (keys.length === 2);
-/* Note: the order is currently wrong. */
-assert (keys[0] === "name");
-assert (keys[1] === "length");
+assert (keys[0] === "length");
+assert (keys[1] === "name");
diff --git a/tests/test262-esnext-excludelist.xml b/tests/test262-esnext-excludelist.xml
index 7c426359a..a9bd0e592 100644
--- a/tests/test262-esnext-excludelist.xml
+++ b/tests/test262-esnext-excludelist.xml
@@ -37,8 +37,6 @@
   <test id="built-ins/Number/prototype/toExponential/return-values.js"><reason></reason></test>
   <test id="built-ins/Number/prototype/toFixed/exactness.js"><reason></reason></test>
   <test id="built-ins/Number/prototype/toPrecision/exponential.js"><reason></reason></test>
-  <test id="built-ins/Object/entries/order-after-define-property.js"><reason></reason></test>
-  <test id="built-ins/Object/keys/order-after-define-property.js"><reason></reason></test>
   <test id="built-ins/Proxy/preventExtensions/trap-is-undefined-target-is-proxy.js"><reason></reason></test>
   <test id="built-ins/String/prototype/matchAll/regexp-is-undefined.js"><reason></reason></test>
   <test id="built-ins/String/prototype/normalize/form-is-not-valid-throws.js"><reason></reason></test>