diff --git a/src/Symfony/Component/HttpFoundation/Session/Storage/MockArraySessionStorage.php b/src/Symfony/Component/HttpFoundation/Session/Storage/MockArraySessionStorage.php
index 918735601d..2e5c0fedc7 100644
--- a/src/Symfony/Component/HttpFoundation/Session/Storage/MockArraySessionStorage.php
+++ b/src/Symfony/Component/HttpFoundation/Session/Storage/MockArraySessionStorage.php
@@ -89,7 +89,7 @@ class MockArraySessionStorage implements SessionStorageInterface
      */
     public function start()
     {
-        if ($this->started && !$this->closed) {
+        if ($this->started) {
             return true;
         }
 
diff --git a/src/Symfony/Component/HttpFoundation/Session/Storage/NativeSessionStorage.php b/src/Symfony/Component/HttpFoundation/Session/Storage/NativeSessionStorage.php
index b1766503f1..7a0c7a85e4 100644
--- a/src/Symfony/Component/HttpFoundation/Session/Storage/NativeSessionStorage.php
+++ b/src/Symfony/Component/HttpFoundation/Session/Storage/NativeSessionStorage.php
@@ -126,7 +126,7 @@ class NativeSessionStorage implements SessionStorageInterface
      */
     public function start()
     {
-        if ($this->started && !$this->closed) {
+        if ($this->started) {
             return true;
         }
 
@@ -134,7 +134,7 @@ class NativeSessionStorage implements SessionStorageInterface
             throw new \RuntimeException('Failed to start the session: already started by PHP.');
         }
 
-        if (PHP_VERSION_ID < 50400 && isset($_SESSION) && session_id()) {
+        if (PHP_VERSION_ID < 50400 && !$this->closed && isset($_SESSION) && session_id()) {
             // not 100% fool-proof, but is the most reliable way to determine if a session is active in PHP 5.3
             throw new \RuntimeException('Failed to start the session: already started by PHP ($_SESSION is set).');
         }
@@ -162,10 +162,6 @@ class NativeSessionStorage implements SessionStorageInterface
      */
     public function getId()
     {
-        if (!$this->started && !$this->closed) {
-            return ''; // returning empty is consistent with session_id() behaviour
-        }
-
         return $this->saveHandler->getId();
     }
 
diff --git a/src/Symfony/Component/HttpFoundation/Session/Storage/PhpBridgeSessionStorage.php b/src/Symfony/Component/HttpFoundation/Session/Storage/PhpBridgeSessionStorage.php
index 6b5ad65056..6554578c6d 100644
--- a/src/Symfony/Component/HttpFoundation/Session/Storage/PhpBridgeSessionStorage.php
+++ b/src/Symfony/Component/HttpFoundation/Session/Storage/PhpBridgeSessionStorage.php
@@ -38,7 +38,7 @@ class PhpBridgeSessionStorage extends NativeSessionStorage
      */
     public function start()
     {
-        if ($this->started && !$this->closed) {
+        if ($this->started) {
             return true;
         }
 
diff --git a/src/Symfony/Component/HttpFoundation/Tests/Session/Storage/NativeSessionStorageTest.php b/src/Symfony/Component/HttpFoundation/Tests/Session/Storage/NativeSessionStorageTest.php
index 1e79812118..e74f52cb3b 100644
--- a/src/Symfony/Component/HttpFoundation/Tests/Session/Storage/NativeSessionStorageTest.php
+++ b/src/Symfony/Component/HttpFoundation/Tests/Session/Storage/NativeSessionStorageTest.php
@@ -85,13 +85,15 @@ class NativeSessionStorageTest extends \PHPUnit_Framework_TestCase
     public function testGetId()
     {
         $storage = $this->getStorage();
-        $this->assertEquals('', $storage->getId());
+        $this->assertSame('', $storage->getId(), 'Empty ID before starting session');
 
         $storage->start();
-        $this->assertNotEquals('', $storage->getId());
+        $id = $storage->getId();
+        $this->assertInternalType('string', $id);
+        $this->assertNotSame('', $id);
 
         $storage->save();
-        $this->assertNotEquals('', $storage->getId());
+        $this->assertSame($id, $storage->getId(), 'ID stays after saving session');
     }
 
     public function testRegenerate()
@@ -209,35 +211,8 @@ class NativeSessionStorageTest extends \PHPUnit_Framework_TestCase
     /**
      * @expectedException \RuntimeException
      */
-    public function testStartedOutside53()
+    public function testStartedOutside()
     {
-        if (PHP_VERSION_ID >= 50400) {
-            $this->markTestSkipped('Test skipped, for PHP 5.3 only.');
-        }
-
-        $storage = $this->getStorage();
-
-        $this->assertFalse(isset($_SESSION));
-
-        session_start();
-        $this->assertTrue(isset($_SESSION));
-        // PHP session might have started, but the storage driver has not, so false is correct here
-        $this->assertFalse($storage->isStarted());
-
-        $key = $storage->getMetadataBag()->getStorageKey();
-        $this->assertFalse(isset($_SESSION[$key]));
-        $storage->start();
-    }
-
-    /**
-     * @expectedException \RuntimeException
-     */
-    public function testCanStartOutside54()
-    {
-        if (PHP_VERSION_ID < 50400) {
-            $this->markTestSkipped('Test skipped, for PHP 5.4 only.');
-        }
-
         $storage = $this->getStorage();
 
         $this->assertFalse(isset($_SESSION));
@@ -246,7 +221,10 @@ class NativeSessionStorageTest extends \PHPUnit_Framework_TestCase
 
         session_start();
         $this->assertTrue(isset($_SESSION));
-        $this->assertTrue($storage->getSaveHandler()->isActive());
+        if (PHP_VERSION_ID >= 50400) {
+            // this only works in PHP >= 5.4 where session_status is available
+            $this->assertTrue($storage->getSaveHandler()->isActive());
+        }
         // PHP session might have started, but the storage driver has not, so false is correct here
         $this->assertFalse($storage->isStarted());
 
@@ -254,4 +232,16 @@ class NativeSessionStorageTest extends \PHPUnit_Framework_TestCase
         $this->assertFalse(isset($_SESSION[$key]));
         $storage->start();
     }
+
+    public function testRestart()
+    {
+        $storage = $this->getStorage();
+        $storage->start();
+        $id = $storage->getId();
+        $storage->getBag('attributes')->set('lucky', 7);
+        $storage->save();
+        $storage->start();
+        $this->assertSame($id, $storage->getId(), 'Same session ID after restarting');
+        $this->assertSame(7, $storage->getBag('attributes')->get('lucky'), 'Data still available');
+    }
 }