Note that this patch would have to be sent out to all users though, since I don't think there is an authentication mechanism that lets them send out different u

Note that this patch would have to be sent out to all users though, since I don't think there is an authentication mechanism that lets them send out different upgrades to different users. And if your whole business is a secure OS, it's a very risky proposition: you get caught doing this once, and your reputation is gone forever.