Earlier quoted context omitted.
Transferring signed packages over TLS only prevents the attacker from observing which particular packages are being updated, and that’s assuming the padding alone is sufficient to obscure identification by size. Otherwise signing packages is actually preferred, because you can do it offline, so that hacking the server is not enough to push malicious code.
But that assumes hardware vendors' signature verification code is correct -- and crypto is really hard to get right
Is it really that hard? Assuming you generate a public/private key, there's openssl RSA_sign and RSA_verify whose interfaces are pretty simple, clear and well documented. There's a difference between "I'm going to write a new way to do asymmetric encryption" which is really hard, and "I'm going to use RSA to verify/sign a binary" which is really easy. I'm seeing a tendency to say that crypto is hard for anything that has to do with crypto which is not the case. While erring on the side of caution is commendable, let's not push vigilance to the point where taking the hash of a file is considered hard crypto to get right.