Magento: white screen, 404 errors
add to index.php
ini_set('error_reporting', E_ERROR);
register_shutdown_function("fatal_handler");
function fatal_handler() {
$error = error_get_last();
echo("<pre>");
print_r($error);
}
via: https://stackoverflow.com/questions/4784117/magento-how-to-debug-blank-white-screen
