diff --git a/core/includes/bootstrap.inc b/core/includes/bootstrap.inc
index eac2f97..1a00261 100644
--- a/core/includes/bootstrap.inc
+++ b/core/includes/bootstrap.inc
@@ -2509,7 +2509,15 @@ function state() {
  * @return Drupal\Core\TypedData\TypedDataManager
  */
 function typed_data() {
-  return drupal_container()->get('typed_data');
+  // Use the advanced drupal_static() pattern, since this is called very often.
+  static $drupal_static_fast;
+  if (!isset($drupal_static_fast)) {
+    $drupal_static_fast['manager'] = &drupal_static(__FUNCTION__);
+  }
+  if (!isset($drupal_static_fast['manager'])) {
+    $drupal_static_fast['manager'] = drupal_container()->get('typed_data');
+  }
+  return $drupal_static_fast['manager'];
 }
 
 /**
diff --git a/core/lib/Drupal/Core/Entity/DatabaseStorageControllerNG.php b/core/lib/Drupal/Core/Entity/DatabaseStorageControllerNG.php
index 0145d1c..6b6d5ff 100644
--- a/core/lib/Drupal/Core/Entity/DatabaseStorageControllerNG.php
+++ b/core/lib/Drupal/Core/Entity/DatabaseStorageControllerNG.php
@@ -109,19 +109,20 @@ protected function attachLoad(&$queried_entities, $load_revision = FALSE) {
 
     // Attach fields.
     if ($this->entityInfo['fieldable']) {
+      // Prepare BC compatible entities for field API.
+      $bc_entities = array();
+      foreach ($queried_entities as $key => $entity) {
+        $bc_entities[$key] = $entity->getBCEntity();
+      }
+
       if ($load_revision) {
-        field_attach_load_revision($this->entityType, $queried_entities);
+        field_attach_load_revision($this->entityType, $bc_entities);
       }
       else {
-        field_attach_load($this->entityType, $queried_entities);
+        field_attach_load($this->entityType, $bc_entities);
       }
     }
 
-    // Loading is finished, so disable compatibility mode now.
-    foreach ($queried_entities as $entity) {
-      $entity->setCompatibilityMode(FALSE);
-    }
-
     // Call hook_entity_load().
     foreach (module_implements('entity_load') as $module) {
       $function = $module . '_entity_load';
@@ -145,12 +146,10 @@ protected function attachLoad(&$queried_entities, $load_revision = FALSE) {
   protected function mapFromStorageRecords(array $records) {
 
     foreach ($records as $id => $record) {
-      $entity = new $this->entityClass(array(), $this->entityType);
-      $entity->setCompatibilityMode(TRUE);
-
       foreach ($record as $name => $value) {
-        $entity->{$name}[LANGUAGE_DEFAULT][0]['value'] = $value;
+        $values[$name][LANGUAGE_DEFAULT][0]['value'] = $value;
       }
+      $entity = new $this->entityClass($values, $this->entityType);
       $records[$id] = $entity;
     }
     return $records;
@@ -174,11 +173,6 @@ public function save(EntityInterface $entity) {
 
       // Create the storage record to be saved.
       $record = $this->maptoStorageRecord($entity);
-      // Update the original values so that the compatibility mode works with
-      // the update values, what is required by field API attachers.
-      // @todo Once field API has been converted to use the Field API, move
-      // this after insert/update hooks.
-      $entity->updateOriginalValues();
 
       if (!$entity->isNew()) {
         $return = drupal_write_record($this->entityInfo['base_table'], $record, $this->idKey);
@@ -196,6 +190,7 @@ public function save(EntityInterface $entity) {
         $this->postSave($entity, FALSE);
         $this->invokeHook('insert', $entity);
       }
+      $entity->updateOriginalValues();
 
       // Ignore slave server temporarily.
       db_ignore_slave();
@@ -218,9 +213,7 @@ public function save(EntityInterface $entity) {
    */
   protected function invokeHook($hook, EntityInterface $entity) {
     if (!empty($this->entityInfo['fieldable']) && function_exists($function = 'field_attach_' . $hook)) {
-      $entity->setCompatibilityMode(TRUE);
-      $function($this->entityType, $entity);
-      $entity->setCompatibilityMode(FALSE);
+      $function($this->entityType, $entity->getBCEntity());
     }
 
     // Invoke the hook.
diff --git a/core/lib/Drupal/Core/Entity/Entity.php b/core/lib/Drupal/Core/Entity/Entity.php
index 710792f..55402e2 100644
--- a/core/lib/Drupal/Core/Entity/Entity.php
+++ b/core/lib/Drupal/Core/Entity/Entity.php
@@ -364,4 +364,18 @@ public function isDefaultRevision($new_value = NULL) {
     }
     return $return;
   }
+
+  /**
+   * Implements Drupal\Core\Entity\EntityInterface::getBCEntity().
+   */
+  public function getBCEntity() {
+    return $this;
+  }
+
+  /**
+   * Implements Drupal\Core\Entity\EntityInterface::getOriginalEntity().
+   */
+  public function getOriginalEntity() {
+    return $this;
+  }
 }
diff --git a/core/lib/Drupal/Core/Entity/EntityBCDecorator.php b/core/lib/Drupal/Core/Entity/EntityBCDecorator.php
new file mode 100644
index 0000000..1179ff8
--- /dev/null
+++ b/core/lib/Drupal/Core/Entity/EntityBCDecorator.php
@@ -0,0 +1,325 @@
+<?php
+
+/**
+ * @file
+ * Definition of Drupal\Core\Entity\EntityBCDecorator.
+ */
+
+namespace Drupal\Core\Entity;
+
+use IteratorAggregate;
+use Drupal\Core\Entity\EntityInterface;
+
+/**
+ * Implements a decorator providing backwards compatible entity field access.
+ *
+ * Allows using entities converted to the new Entity Field API with the Drupal 7
+ * way of accessing ways fields or properties.
+ */
+class EntityBCDecorator implements IteratorAggregate, EntityInterface {
+
+  /**
+   * The EntityInterface object being decorated.
+   *
+   * @var \Drupal\Core\Entity\EntityInterface
+   */
+  protected $decorated;
+
+  /**
+   * A reference on the plain field values, as exposed for BC.
+   *
+   * @var array
+   */
+  protected $values;
+
+  /**
+   * A reference on the array of field objects of the entity.
+   *
+   * @var array
+   */
+  protected $fields;
+
+  /**
+   * Constructs a Drupal\Core\Entity\EntityCompatibilityDecorator object.
+   *
+   * @param \Drupal\Core\Entity\EntityInterface $decorated
+   *   The decorated entity.
+   * @param array $values
+   *   A reference on the plain field values, as exposed for BC.
+   * @param array $fields
+   *   A reference on the array of field objects of the entity.
+   */
+  function __construct(EntityInterface $decorated, &$values, &$fields) {
+    $this->decorated = $decorated;
+    $this->values = &$values;
+    $this->fields = &$fields;
+  }
+
+  /**
+   * Overrides Entity::getOriginalEntity().
+   */
+  public function getOriginalEntity() {
+    return $this->decorated;
+  }
+
+  /**
+   * Overrides Entity::getBCEntity().
+   */
+  public function getBCEntity() {
+    return $this;
+  }
+
+  /**
+   * Allows direct access to the plain values, as done in Drupal 7.
+   */
+  public function &__get($name) {
+    if (!empty($this->fields[$name])) {
+      foreach ($this->fields[$name] as $langcode => $field) {
+        $this->values[$name][$langcode] = $field->getValue();
+      }
+      // Values might be changed by reference, so remove the field object to
+      // avoid them becoming out of sync.
+      unset($this->fields[$name]);
+    }
+    if (!isset($this->values[$name])) {
+      $this->values[$name] = NULL;
+    }
+    return $this->values[$name];
+  }
+
+  /**
+   * Allows directly writing to the plain values, as done in Drupal 7.
+   */
+  public function __set($name, $value) {
+    if (is_array($value) && $definition = $this->decorated->getPropertyDefinition($name)) {
+      // If field API sets a value with a langcode in entity language, move it
+      // to LANGUAGE_DEFAULT.
+      foreach ($value as $langcode => $data) {
+        if ($langcode != LANGUAGE_DEFAULT && $langcode == $this->decorated->language()->langcode) {
+          $value[LANGUAGE_DEFAULT] = $data;
+          unset($value[$langcode]);
+        }
+      }
+    }
+
+    $this->values[$name] = $value;
+    unset($this->fields[$name]);
+  }
+
+  /**
+   * Magic method.
+   */
+  public function __isset($name) {
+    return isset($this->values[$name]);
+  }
+
+  /**
+   * Magic method.
+   */
+  public function __unset($name) {
+    unset($this->values[$name]);
+  }
+
+  /**
+   * Forwards the call to the decorated entity.
+   */
+  public function access(\Drupal\user\User $account = NULL) {
+    return $this->decorated->access($account);
+  }
+
+  /**
+   * Forwards the call to the decorated entity.
+   */
+  public function get($property_name) {
+    return $this->decorated->get($property_name);
+  }
+
+  /**
+   * Forwards the call to the decorated entity.
+   */
+  public function set($property_name, $value) {
+    return $this->decorated->set($property_name, $value);
+  }
+
+  /**
+   * Forwards the call to the decorated entity.
+   */
+  public function getProperties($include_computed = FALSE) {
+    return $this->decorated->getProperties($include_computed);
+  }
+
+  /**
+   * Forwards the call to the decorated entity.
+   */
+  public function getPropertyValues() {
+    return $this->decorated->getPropertyValues();
+  }
+
+  /**
+   * Forwards the call to the decorated entity.
+   */
+  public function setPropertyValues($values) {
+    return $this->decorated->setPropertyValues($values);
+  }
+
+  /**
+   * Forwards the call to the decorated entity.
+   */
+  public function getPropertyDefinition($name) {
+    return $this->decorated->getPropertyDefinition($name);
+  }
+
+  /**
+   * Forwards the call to the decorated entity.
+   */
+  public function getPropertyDefinitions() {
+    return $this->decorated->getPropertyDefinitions();
+  }
+
+  /**
+   * Forwards the call to the decorated entity.
+   */
+  public function isEmpty() {
+    return $this->decorated->isEmpty();
+  }
+
+  /**
+   * Forwards the call to the decorated entity.
+   */
+  public function getIterator() {
+    return $this->decorated->getIterator();
+  }
+
+  /**
+   * Forwards the call to the decorated entity.
+   */
+  public function id() {
+    return $this->decorated->id();
+  }
+
+  /**
+   * Forwards the call to the decorated entity.
+   */
+  public function uuid() {
+    return $this->decorated->uuid();
+  }
+
+  /**
+   * Forwards the call to the decorated entity.
+   */
+  public function isNew() {
+    return $this->decorated->isNew();
+  }
+
+  /**
+   * Forwards the call to the decorated entity.
+   */
+  public function isNewRevision() {
+    return $this->decorated->isNewRevision();
+  }
+
+  /**
+   * Forwards the call to the decorated entity.
+   */
+  public function setNewRevision($value = TRUE) {
+    return $this->decorated->setNewRevision($value);
+  }
+
+  /**
+   * Forwards the call to the decorated entity.
+   */
+  public function enforceIsNew($value = TRUE) {
+    return $this->decorated->enforceIsNew($value);
+  }
+
+  /**
+   * Forwards the call to the decorated entity.
+   */
+  public function entityType() {
+    return $this->decorated->entityType();
+  }
+
+  /**
+   * Forwards the call to the decorated entity.
+   */
+  public function bundle() {
+    return $this->decorated->bundle();
+  }
+
+  /**
+   * Forwards the call to the decorated entity.
+   */
+  public function label($langcode = NULL) {
+    return $this->decorated->label();
+  }
+
+  /**
+   * Forwards the call to the decorated entity.
+   */
+  public function uri() {
+    return $this->decorated->uri();
+  }
+
+  /**
+   * Forwards the call to the decorated entity.
+   */
+  public function save() {
+    return $this->decorated->save();
+  }
+
+  /**
+   * Forwards the call to the decorated entity.
+   */
+  public function delete() {
+    return $this->decorated->delete();
+  }
+
+  /**
+   * Forwards the call to the decorated entity.
+   */
+  public function createDuplicate() {
+    return $this->decorated->createDuplicate();
+  }
+
+  /**
+   * Forwards the call to the decorated entity.
+   */
+  public function entityInfo() {
+    return $this->decorated->entityInfo();
+  }
+
+  /**
+   * Forwards the call to the decorated entity.
+   */
+  public function getRevisionId() {
+    return $this->decorated->getRevisionId();
+  }
+
+  /**
+   * Forwards the call to the decorated entity.
+   */
+  public function isDefaultRevision($new_value = NULL) {
+    return $this->decorated->isDefaultRevision();
+  }
+
+  /**
+   * Forwards the call to the decorated entity.
+   */
+  public function language() {
+    return $this->decorated->language();
+  }
+
+  /**
+   * Forwards the call to the decorated entity.
+   */
+  public function getTranslationLanguages($include_default = TRUE) {
+    return $this->decorated->getTranslationLanguages($include_default);
+  }
+
+  /**
+   * Forwards the call to the decorated entity.
+   */
+  public function getTranslation($langcode, $strict = TRUE) {
+    return $this->decorated->getTranslation($langcode, $strict);
+  }
+}
diff --git a/core/lib/Drupal/Core/Entity/EntityFormControllerNG.php b/core/lib/Drupal/Core/Entity/EntityFormControllerNG.php
index d06614d..6d1cd51 100644
--- a/core/lib/Drupal/Core/Entity/EntityFormControllerNG.php
+++ b/core/lib/Drupal/Core/Entity/EntityFormControllerNG.php
@@ -23,9 +23,7 @@ public function form(array $form, array &$form_state, EntityInterface $entity) {
     // entity properties.
     $info = $entity->entityInfo();
     if (!empty($info['fieldable'])) {
-      $entity->setCompatibilityMode(TRUE);
-      field_attach_form($entity->entityType(), $entity, $form, $form_state, $this->getFormLangcode($form_state));
-      $entity->setCompatibilityMode(FALSE);
+      field_attach_form($entity->entityType(), $entity->getBCEntity(), $form, $form_state, $this->getFormLangcode($form_state));
     }
     return $form;
   }
@@ -40,9 +38,7 @@ public function validate(array $form, array &$form_state) {
     $info = $entity->entityInfo();
 
     if (!empty($info['fieldable'])) {
-      $entity->setCompatibilityMode(TRUE);
-      field_attach_form_validate($entity->entityType(), $entity, $form, $form_state);
-      $entity->setCompatibilityMode(FALSE);
+      field_attach_form_validate($entity->entityType(), $entity->getBCEntity(), $form, $form_state);
     }
 
     // @todo Remove this.
@@ -77,9 +73,7 @@ public function buildEntity(array $form, array &$form_state) {
 
     // Copy field values to the entity.
     if ($info['fieldable']) {
-      $entity->setCompatibilityMode(TRUE);
-      field_attach_submit($entity_type, $entity, $form, $form_state);
-      $entity->setCompatibilityMode(FALSE);
+      field_attach_submit($entity_type, $entity->getBCEntity(), $form, $form_state);
     }
     return $entity;
   }
diff --git a/core/lib/Drupal/Core/Entity/EntityInterface.php b/core/lib/Drupal/Core/Entity/EntityInterface.php
index 9b751d4..e7e46fc 100644
--- a/core/lib/Drupal/Core/Entity/EntityInterface.php
+++ b/core/lib/Drupal/Core/Entity/EntityInterface.php
@@ -181,4 +181,22 @@ public function getRevisionId();
    *   $new_value was passed, the previous value is returned.
    */
   public function isDefaultRevision($new_value = NULL);
+
+  /**
+   * Gets a backward compatibility decorator entity.
+   *
+   * @see \Drupal\Core\Entity\EntityInterface::getOriginalEntity()
+   *
+   * @return \Drupal\Core\Entity\EntityInterface
+   */
+  public function getBCEntity();
+
+  /**
+   * Removes any possibly (backward compatibility) decorator in use.
+   *
+   * @see \Drupal\Core\Entity\EntityInterface::getBCEntity()
+   *
+   * @return \Drupal\Core\Entity\EntityInterface
+   */
+  public function getOriginalEntity();
 }
diff --git a/core/lib/Drupal/Core/Entity/EntityNG.php b/core/lib/Drupal/Core/Entity/EntityNG.php
index 6541d44..e3aff9b 100644
--- a/core/lib/Drupal/Core/Entity/EntityNG.php
+++ b/core/lib/Drupal/Core/Entity/EntityNG.php
@@ -50,21 +50,25 @@ class EntityNG extends Entity {
   protected $fields = array();
 
   /**
-   * Whether the entity is in pre-Entity Field API compatibility mode.
+   * An instance of the backward compatibility decorator.
    *
-   * If set to TRUE, field values are written directly to $this->values, thus
-   * must be plain property values keyed by language code. This must be enabled
-   * when calling legacy field API attachers.
+   * @var EntityBCDecorator
+   */
+  protected $bcEntity;
+
+  /**
+   * Static cache for property definitions.
    *
-   * @var bool
+   * @var array
    */
-  protected $compatibilityMode = FALSE;
+  protected $fieldDefinitions;
 
   /**
    * Overrides Entity::__construct().
    */
   public function __construct(array $values, $entity_type) {
-    parent::__construct($values, $entity_type);
+    parent::__construct(array(), $entity_type);
+    $this->values = $values + $this->values;
     $this->init();
   }
 
@@ -166,6 +170,11 @@ public function getIterator() {
    * Implements ComplexDataInterface::getPropertyDefinition().
    */
   public function getPropertyDefinition($name) {
+    // Try to read from static cache.
+    if (isset($this->fieldDefinitions)) {
+      return isset($this->fieldDefinitions[$name]) ? $this->fieldDefinitions[$name] : FALSE;
+    }
+
     // First try getting property definitions which apply to all entities of
     // this type. Then if this fails add in definitions of optional properties
     // as well. That way we can use property definitions of base properties
@@ -185,10 +194,13 @@ public function getPropertyDefinition($name) {
    * Implements ComplexDataInterface::getPropertyDefinitions().
    */
   public function getPropertyDefinitions() {
-    return entity_get_controller($this->entityType)->getFieldDefinitions(array(
-      'entity type' => $this->entityType,
-      'bundle' => $this->bundle(),
-    ));
+    if (!isset($this->fieldDefinitions)) {
+      $this->fieldDefinitions = entity_get_controller($this->entityType)->getFieldDefinitions(array(
+        'entity type' => $this->entityType,
+        'bundle' => $this->bundle(),
+      ));
+    }
+    return $this->fieldDefinitions;
   }
 
   /**
@@ -306,48 +318,17 @@ public function translations() {
   }
 
   /**
-   * Enables or disable the compatibility mode.
-   *
-   * @param bool $enabled
-   *   Whether to enable the mode.
-   *
-   * @see EntityNG::compatibilityMode
+   * Overrides Entity::getBCEntity().
    */
-  public function setCompatibilityMode($enabled) {
-    if (!$this->compatibilityMode && $enabled) {
-      $this->updateOriginalValues();
-      $this->fields = array();
-    }
-    elseif ($this->compatibilityMode && !$enabled) {
-      // Field API might have written values with a language key, which should
-      // haved used LANGUAGE_DEFAULT. Fix that by moving values around.
-      $langcode = $this->get('langcode')->value;
-
-      if ($langcode != LANGUAGE_DEFAULT) {
-        foreach ($this->getPropertyDefinitions() as $name => $definition) {
-          if (isset($this->values[$name][$langcode]) && is_array($this->values[$name][$langcode])) {
-            $this->values[$name][LANGUAGE_DEFAULT] = $this->values[$name][$langcode];
-            unset($this->values[$name][$langcode]);
-          }
-        }
-      }
+  public function getBCEntity() {
+    if (!isset($this->bcEntity)) {
+      $this->bcEntity = new EntityBCDecorator($this, $this->values, $this->fields);
     }
-
-    $this->compatibilityMode = (bool) $enabled;
-  }
-
-  /**
-   * Returns whether the compatibility mode is active.
-   */
-  public function getCompatibilityMode() {
-    return $this->compatibilityMode;
+    return $this->bcEntity;
   }
 
   /**
    * Updates the original values with the interim changes.
-   *
-   * Note: This should be called to make sure compatibility mode uses latest
-   * values.
    */
   public function updateOriginalValues() {
     if (!$this->fields) {
@@ -368,12 +349,6 @@ public function updateOriginalValues() {
    * For compatibility mode to work this must return a reference.
    */
   public function &__get($name) {
-    if ($this->compatibilityMode) {
-      if (!isset($this->values[$name])) {
-        $this->values[$name] = NULL;
-      }
-      return $this->values[$name];
-    }
     if (isset($this->fields[$name][LANGUAGE_DEFAULT])) {
       return $this->fields[$name][LANGUAGE_DEFAULT];
     }
@@ -398,10 +373,7 @@ public function __set($name, $value) {
       $value = $value->getValue();
     }
 
-    if ($this->compatibilityMode) {
-      $this->values[$name] = $value;
-    }
-    elseif (isset($this->fields[$name][LANGUAGE_DEFAULT])) {
+    if (isset($this->fields[$name][LANGUAGE_DEFAULT])) {
       $this->fields[$name][LANGUAGE_DEFAULT]->setValue($value);
     }
     elseif ($this->getPropertyDefinition($name)) {
@@ -418,7 +390,7 @@ public function __set($name, $value) {
    * Magic method.
    */
   public function __isset($name) {
-    if (!$this->compatibilityMode && $this->getPropertyDefinition($name)) {
+    if ($this->getPropertyDefinition($name)) {
       return (bool) count($this->get($name));
     }
     else {
@@ -430,7 +402,7 @@ public function __isset($name) {
    * Magic method.
    */
   public function __unset($name) {
-    if (!$this->compatibilityMode && $this->getPropertyDefinition($name)) {
+    if ($this->getPropertyDefinition($name)) {
       $this->get($name)->setValue(array());
     }
     else {
@@ -458,13 +430,28 @@ public function createDuplicate() {
    * Implements a deep clone.
    */
   public function __clone() {
+    unset($this->bcEntity);
+
+    // Make sure the fields and values variables are copies, not references.
+    // This is necessary as they are turned into references when they are passed
+    // by reference to the EntityBCDecorator.
+    $values = array();
+    foreach ($this->values as $name => $value) {
+      $values[$name] = $value;
+    }
+    unset($this->values);
+    $this->values = $values;
+
+    $fields = array();
     foreach ($this->fields as $name => $properties) {
       foreach ($properties as $langcode => $property) {
-        $this->fields[$name][$langcode] = clone $property;
+        $fields[$name][$langcode] = clone $property;
         if ($property instanceof ContextAwareInterface) {
-          $this->fields[$name][$langcode]->setParent($this);
+          $fields[$name][$langcode]->setParent($this);
         }
       }
     }
+    unset($this->fields);
+    $this->fields = $fields;
   }
 }
diff --git a/core/modules/comment/comment.module b/core/modules/comment/comment.module
index 910ef84..5f929f3 100644
--- a/core/modules/comment/comment.module
+++ b/core/modules/comment/comment.module
@@ -1670,9 +1670,7 @@ function template_preprocess_comment(&$variables) {
   }
 
   // Preprocess fields.
-  $comment->setCompatibilityMode(TRUE);
-  field_attach_preprocess('comment', $comment, $variables['elements'], $variables);
-  $comment->setCompatibilityMode(FALSE);
+  field_attach_preprocess('comment', $comment->getBCEntity(), $variables['elements'], $variables);
 
   // Helpful $content variable for templates.
   foreach (element_children($variables['elements']) as $key) {
diff --git a/core/modules/field/field.attach.inc b/core/modules/field/field.attach.inc
index 14ea9ad..beaf7a5 100644
--- a/core/modules/field/field.attach.inc
+++ b/core/modules/field/field.attach.inc
@@ -8,6 +8,7 @@
 use Drupal\field\FieldValidationException;
 use Drupal\Core\Entity\EntityInterface;
 use Drupal\Core\Entity\EntityNG;
+use Drupal\Core\Entity\EntityBCDecorator;
 
 /**
  * @defgroup field_storage Field Storage API
@@ -1385,12 +1386,8 @@ function field_attach_prepare_view($entity_type, $entities, $view_mode, $langcod
       // Add this entity to the items to be prepared.
       $prepare[$id] = $entity;
 
-      // Enable compatibility mode if necessary.
-      // @todo: Remove this once all entity types have been converted to the
-      // new entity field API.
-      if ($entity instanceof EntityNG) {
-        $entity->setCompatibilityMode(TRUE);
-      }
+      // Enable BC if necessary.
+      $entity = $entity->getBCEntity();
 
       // Determine the actual language code to display for each field, given the
       // language codes available in the field data.
@@ -1457,6 +1454,8 @@ function field_attach_prepare_view($entity_type, $entities, $view_mode, $langcod
  *   A renderable array for the field values.
  */
 function field_attach_view($entity_type, EntityInterface $entity, $view_mode, $langcode = NULL, array $options = array()) {
+  // Enable BC if necessary.
+  $entity = $entity->getBCEntity();
   // Determine the actual language code to display for each field, given the
   // language codes available in the field data.
   $options['langcode'] = field_language($entity_type, $entity, NULL, $langcode);
@@ -1465,12 +1464,8 @@ function field_attach_view($entity_type, EntityInterface $entity, $view_mode, $l
   $null = NULL;
   $output = field_invoke_method('view', _field_invoke_formatter_target($view_mode), $entity, $view_mode, $null, $options);
 
-  // Disable compatibility mode if necessary.
-  // @todo: Remove this once all entity types have been converted to the
-  // new entity field API.
-  if ($entity instanceof EntityNG) {
-    $entity->setCompatibilityMode(FALSE);
-  }
+  // Remove the BC layer now.
+  $entity = $entity->getOriginalEntity();
 
   // Add custom weight handling.
   $output['#pre_render'][] = '_field_extra_fields_pre_render';
diff --git a/core/modules/system/tests/modules/entity_test/lib/Drupal/entity_test/EntityTestStorageController.php b/core/modules/system/tests/modules/entity_test/lib/Drupal/entity_test/EntityTestStorageController.php
index fbb735d..65ef649 100644
--- a/core/modules/system/tests/modules/entity_test/lib/Drupal/entity_test/EntityTestStorageController.php
+++ b/core/modules/system/tests/modules/entity_test/lib/Drupal/entity_test/EntityTestStorageController.php
@@ -48,32 +48,41 @@ protected function buildPropertyQuery(QueryInterface $entity_query, array $value
    *   An array of entity objects implementing the EntityInterface.
    */
   protected function mapFromStorageRecords(array $records) {
-    $records = parent::mapFromStorageRecords($records);
-
-    // Load data of translatable properties.
-    $this->attachPropertyData($records);
+    $property_values = $this->getPropertyValues($records);
+
+    foreach ($records as $id => $record) {
+      $values = $property_values[$id];
+      foreach ($record as $name => $value) {
+        $values[$name][LANGUAGE_DEFAULT][0]['value'] = $value;
+      }
+      $entity = new $this->entityClass($values, $this->entityType);
+      $records[$id] = $entity;
+    }
     return $records;
   }
 
   /**
    * Attaches property data in all languages for translatable properties.
    */
-  protected function attachPropertyData(&$queried_entities) {
+  protected function getPropertyValues($records) {
     $data = db_select('entity_test_property_data', 'data', array('fetch' => PDO::FETCH_ASSOC))
       ->fields('data')
-      ->condition('id', array_keys($queried_entities))
+      ->condition('id', array_keys($records))
       ->orderBy('data.id')
       ->execute();
 
+    $property_values = array();
+
     foreach ($data as $values) {
       $id = $values['id'];
       // Field values in default language are stored with
       // LANGUAGE_DEFAULT as key.
       $langcode = empty($values['default_langcode']) ? $values['langcode'] : LANGUAGE_DEFAULT;
 
-      $queried_entities[$id]->name[$langcode][0]['value'] = $values['name'];
-      $queried_entities[$id]->user_id[$langcode][0]['value'] = $values['user_id'];
+      $property_values[$id]['name'][$langcode][0]['value'] = $values['name'];
+      $property_values[$id]['user_id'][$langcode][0]['value'] = $values['user_id'];
     }
+    return $property_values;
   }
 
   /**