diff --git a/classes/Language.php b/classes/Language.php
index 6f0469774..a0683873b 100644
--- a/classes/Language.php
+++ b/classes/Language.php
@@ -788,11 +788,11 @@ class LanguageCore extends ObjectModel
 		$lang_pack_ok = false;
 		$errors = array();
 		$file = _PS_TRANSLATIONS_DIR_.$iso.'.gzip';
-		if (!$lang_pack_link = Tools::file_get_contents('http://www.prestashop.com/download/lang_packs/get_language_pack.php?version='.$version.'&iso_lang='.$iso))
+		if (!$lang_pack_link = Tools::file_get_contents('http://www.prestashop.com/download/lang_packs/get_language_pack.php?version='.$version.'&iso_lang='.Tools::strtolower($iso)))
 			$errors[] = Tools::displayError('Archive cannot be downloaded from prestashop.com.');
 		elseif (!$lang_pack = Tools::jsonDecode($lang_pack_link))
 			$errors[] = Tools::displayError('Error occurred when language was checked according to your Prestashop version.');
-		elseif ($content = Tools::file_get_contents('http://translations.prestashop.com/download/lang_packs/gzip/'.$lang_pack->version.'/'.$lang_pack->iso_code.'.gzip'))
+		elseif ($content = Tools::file_get_contents('http://translations.prestashop.com/download/lang_packs/gzip/'.$lang_pack->version.'/'.Tools::strtolower($lang_pack->iso_code.'.gzip')))
 			if (!@file_put_contents($file, $content))
 				$errors[] = Tools::displayError('Server does not have permissions for writing.');
 		if (file_exists($file))
diff --git a/controllers/admin/AdminLanguagesController.php b/controllers/admin/AdminLanguagesController.php
index 1db3d4eeb..916942623 100644
--- a/controllers/admin/AdminLanguagesController.php
+++ b/controllers/admin/AdminLanguagesController.php
@@ -489,7 +489,7 @@ class AdminLanguagesControllerCore extends AdminController
 		}
 
 		// Get all iso code available
-		if ($lang_packs = Tools::file_get_contents('http://www.prestashop.com/download/lang_packs/get_language_pack.php?version='.Tools::getValue('ps_version').'&iso_lang='.Tools::getValue('iso_lang')))
+		if ($lang_packs = Tools::file_get_contents('http://www.prestashop.com/download/lang_packs/get_language_pack.php?version='.Tools::getValue('ps_version').'&iso_lang='.Tools::strtolower(Tools::getValue('iso_lang'))))
 		{
 			$result = Tools::jsonDecode($lang_packs);
 			if ($lang_packs !== '' && $result && !isset($result->error))
diff --git a/controllers/admin/AdminTranslationsController.php b/controllers/admin/AdminTranslationsController.php
index 1357aacc0..eaa19d4a1 100644
--- a/controllers/admin/AdminTranslationsController.php
+++ b/controllers/admin/AdminTranslationsController.php
@@ -720,7 +720,7 @@ class AdminTranslationsControllerCore extends AdminController
 		if (Validate::isLangIsoCode($arr_import_lang[0]))
 		{
 			if ($content = Tools::file_get_contents(
-				'http://www.prestashop.com/download/lang_packs/gzip/'.$arr_import_lang[1].'/'.$arr_import_lang[0].'.gzip', false,
+				'http://www.prestashop.com/download/lang_packs/gzip/'.$arr_import_lang[1].'/'.Tools::strtolower($arr_import_lang[0]).'.gzip', false,
 				@stream_context_create(array('http' => array('method' => 'GET', 'timeout' => 5)))))
 			{
 				$file = _PS_TRANSLATIONS_DIR_.$arr_import_lang[0].'.gzip';
diff --git a/js/checkLangPack.js b/js/checkLangPack.js
index 0db7a857a..1bcd6aec7 100644
--- a/js/checkLangPack.js
+++ b/js/checkLangPack.js
@@ -34,7 +34,7 @@ function checkLangPack(token){
 				action:'checkLangPack',
 				token:token,
 				ajax:1,
-				iso_lang:$('#iso_code').val(), 
+				iso_lang:($('#iso_code').val()).toLowerCase(), 
 				ps_version:$('#ps_version').val()
 			},
 			function(ret)
@@ -47,7 +47,7 @@ function checkLangPack(token){
 					message = langPackOk + ' <b>'+content['name'] + '</b>) :'
 						+'<br />' + langPackVersion + ' ' + content['version']
 						+ ' <a href="http://www.prestashop.com/download/lang_packs/gzip/' + content['version'] + '/'
-						+ $('#iso_code').val()+'.gzip" target="_blank" class="link">'+download+'</a><br />' + langPackInfo;
+						+ ($('#iso_code').val()).toLowerCase()+'.gzip" target="_blank" class="link">'+download+'</a><br />' + langPackInfo;
 					$('#lang_pack_msg').html(message);
 					$('#lang_pack_msg').show();
 				}