given the enormous capital cost of doing anything in space ever, I don’t think they’d even do that

The standard thing people refer to as “Secure Boot” allows users to enroll their own keys and thus is not TiVo. The ability to enroll your own keys is the distinguishing feature here - TiVo devices don’t let you do that, so you can’t sign your own thing and run it.

The FSF has various pearl clutching articles from the days of Windows 8 fretting about whether or not users would be able to install their own keys on Secure Boot devices, but here in 2025, most devices allow this. (I’m sure there’s a handful of bizarre laptops or whatever that don’t, but the vast majority of hardware I’ve seen is fine.)

No one’s running their instance here.

speak for yourself