So, KHD allows to bypass "firewall" mods while hacking. If the unit has both AHD+KHD does it mean that the AHD hacking programs also gets such perk (bypassing firewall) or is that limited only to KHD programs? If this perk is limited only to KHD programs does it mean that units with AHD and program upgrade from KHD (Maestro/Lighting/Trinity) also gets "bypass firewall" perk while using said KHD Upgrade program (while still not having KHD device per se) ?
https://forum.corvusbelli.com/threads/multiple-hacking-devices.23823/#post-114260 Short answer: No. Longer answer: No, the ability to ignore Firewalls is inherent to the Killer Hacking Device itself and is not a trait that transfers to the user (unlike e.g. MSV2). The only programs you can ignore Firewalls with are those that <Mary Problems> can use with her Killer Hacking Device.
Perk is limited to Killer Hacking Devices. Not "KHD programs", which is a thing that doesn't exist in Infinity. Take a look at Mary Problems. You'll see upgrade programs are specified per Hacking Device. This means Lighting will ignore Firewall modifiers, but Icebreaker will not, because Icebreaker is used via AHD. This also means Lighting on Deva AHD will not ignore Firewalls. Neither will Maestro on Danavas. Or any other similar example. But if a unit appeared with KHD which had a Icebreaker upgrade program, then that Icebreaker would ignore Firewalls.
Or to answer what I suspect is the hidden question: No, DeFersen don't get to ignore firewalls when using Trinity
