I need a consistency check on an idea:
The bootstrap cyberprogramm (DT p.56) allows the modification of the Format Device Action, so that a targeted device performs certain actions whenever it is booted up.
Now, if you give it the following commands:
Boot up in Silent Running mode, First action: perform complex action reboot.
That should ensure that this device is now unhackable as anyone trying to hack it must first succeed in a matrix perception check to find the silent running icon, before they can try to target it with a matrix action.
Only the owner can see the icon plop up in the matrix and has a chance to give it a command (like detonating a grenade or trace icon)
The only way to beat that would require the hacker to gain to consecutive actions before the grenade takes its first action, which is not really possible (at least I don't know any method to achieve that)