Attempted my first official Z/X battoru (I say attempted because it wasn't completed... neither my friend nor I could deal a damage after an hour had past so we called it a draw-- I blame TCO manual operations for taking too long)
Anyways, we had a question... and the answer is probably extremely obvious so I hope I'm not making a fool of myself. We didn't quite know what boot and reboot meant. At first, I thought it was a reference to the position of the card (stand/sleep), but then I realize that some cards directly state "stand/sleep" as a condition so that idea went out the window. After looking closer, I think it is referring to the timing of when a skill can activate... similarly to auto, act, and cont. effects in Vanguard. If you could either confirm or deny this, I would greatly appreciate it. Thanks.
Reboot is used to refer to card in vertical position or the action of switching a card from horizontal position (a.k.a. Sleep) into the vertical position, basically it is similar to untap in MTG or stand in CFV.
On the other hand, Boot is one of the classification of ability. It is the kind of ability that must be manually activated by the controller, if you are familiar with CFV then it is pretty much similar to [ACT] ability.
P.S.: Maybe you'll want to check the Playing Manual once again in order to familiarize yourself with the game terms. ;)