diff --git a/src/Symfony/Component/HttpFoundation/ParameterBag.php b/src/Symfony/Component/HttpFoundation/ParameterBag.php
index e3be0a9b8b..19d7ee913a 100644
--- a/src/Symfony/Component/HttpFoundation/ParameterBag.php
+++ b/src/Symfony/Component/HttpFoundation/ParameterBag.php
@@ -174,7 +174,7 @@ class ParameterBag implements \IteratorAggregate, \Countable
      * Returns the parameter value converted to boolean.
      *
      * @param string $key     The parameter key
-     * @param mixed  $default The default value if the parameter key does not exist
+     * @param bool   $default The default value if the parameter key does not exist
      *
      * @return bool The filtered value
      */
diff --git a/src/Symfony/Component/HttpFoundation/Response.php b/src/Symfony/Component/HttpFoundation/Response.php
index 832260a51e..f267d1e0e0 100644
--- a/src/Symfony/Component/HttpFoundation/Response.php
+++ b/src/Symfony/Component/HttpFoundation/Response.php
@@ -334,8 +334,9 @@ class Response
 
         // headers
         foreach ($this->headers->allPreserveCaseWithoutCookies() as $name => $values) {
+            $replace = 0 === strcasecmp($name, 'Content-Type');
             foreach ($values as $value) {
-                header($name.': '.$value, false, $this->statusCode);
+                header($name.': '.$value, $replace, $this->statusCode);
             }
         }