diff --git a/src/Symfony/Bridge/PhpUnit/bin/simple-phpunit b/src/Symfony/Bridge/PhpUnit/bin/simple-phpunit
index b9719b268a..49a610ed14 100755
--- a/src/Symfony/Bridge/PhpUnit/bin/simple-phpunit
+++ b/src/Symfony/Bridge/PhpUnit/bin/simple-phpunit
@@ -48,14 +48,14 @@ if (!file_exists("$PHPUNIT_DIR/phpunit-$PHPUNIT_VERSION/phpunit") || md5_file(__
     $zip->extractTo(getcwd());
     $zip->close();
     chdir("phpunit-$PHPUNIT_VERSION");
-    $prevRoot = getenv('COMPOSER_ROOT_VERSION');
-    putenv("COMPOSER_ROOT_VERSION=$PHPUNIT_VERSION");
-    proc_close(proc_open("$COMPOSER remove --no-update ".(getenv('SYMFONY_PHPUNIT_REMOVE') ?: 'phpspec/prophecy symfony/yaml'), array(), $p));
+    passthru("$COMPOSER remove --no-update ".(getenv('SYMFONY_PHPUNIT_REMOVE') ?: 'phpspec/prophecy symfony/yaml'));
     if (5.1 <= $PHPUNIT_VERSION && $PHPUNIT_VERSION < 5.4) {
         passthru("$COMPOSER require --no-update phpunit/phpunit-mock-objects \"~3.1.0\"");
     }
-    proc_close(proc_open("$COMPOSER require --no-update symfony/phpunit-bridge \">=3.2@dev\"", array(), $p));
-    $exit = proc_close(proc_open("$COMPOSER install --no-dev --prefer-dist --no-progress --ansi", array(), $p));
+    passthru("$COMPOSER require --no-update symfony/phpunit-bridge \">=3.2@dev\"");
+    $prevRoot = getenv('COMPOSER_ROOT_VERSION');
+    putenv("COMPOSER_ROOT_VERSION=$PHPUNIT_VERSION");
+    $exit = proc_close(proc_open("$COMPOSER install --no-dev --prefer-dist --no-progress --ansi", array(), $p, getcwd(), null, array('bypass_shell' => true)));
     putenv('COMPOSER_ROOT_VERSION'.(false !== $prevRoot ? '='.$prevRoot : ''));
     if ($exit) {
         exit($exit);