“They then tried to offer me journalistic privilege,” which he also flat-out refused.

“The idea was that you tell an ‘independent’ policeman what the passcode is, and where all the privileged documents and contacts are, then they sift through them to decide what to pass to the prosecution,” he says.

The auto reboot is on an 18 hour timer in graphene and iirc a 72 hour timer in ios.

One advice I heard for travelling internationally is to keep your devices clean and have your files encrypted on a server.

Of course a server can be seized too but for crossing a border it's lower risk than having (encrypted) files on a device you are carrying.