As I understand it the manufacturers need to release only the information, nowhere GPLv3 says that the manufacturer should make the process of running custom so

As I understand it the manufacturers need to release only the information, nowhere GPLv3 says that the manufacturer should make the process of running custom software easy or economically viable, just that the information should be available. But as I've said I'm no law expert and I wouldn't put my hand on fire about it.