Now the YouTube team once more confirmed that you can no longer sign in
on old chromecasts. Could of course be that they are just confirming the
users problem, but sound a lot like the tweet the other day. And that is
was not a question to the user, ...
There is still hope that we get this fixed. Looks like they recognize
this as an issue now, just not the standard "Have you tried upgrading"
etc. Or the strange answer yesterday that this is intentionally.