I just noticed that in the midst of the rewrite to make the rules more visual this rule didn't get in. I'll have it up in the next version of the rules.
"If a hacker rolls 3 of the same value then they may reroll without discarding an extra die."
This is so that if you get the minimal odds of getting 3 of the same value, be it backdoors, ones, firewalls or spikes, then you are rewarded and not punished for your unlikely roll.
It was in the previous version of the rules, it just didn't make it into this one.