Here's an interesting question for you fine folks. Does the +3 bts from firewall apply before or after a breaker hack? Rules says that ap applies before partial cover. As well as breaker ammo. They did not reference firewall at all so i think it may be breaker after firewall. Let's use danavas hd+ with maestro as example against a deva hd (bts 3 base) through an enemy repeater. Is the deva bts 5 against the save (3/2+3) or bts 3 against the attack ((3+3)/2).
So RAW: 1. Whenever a rule mentions the value of an Attribute, consider it to mean the final value, obtained after applying all MODs. 2. In game terms, Firewall imposes an additional -3 MOD to the WIP of the trooper who declared the Hacking Attack. Additionally, Firewall grants the target of the Attack a +3 BTS MOD. 3. Breaker special ammo makes no special exception for this MOD, so the MOD applies before Breaker halves it.
It's a weird inconsistency I sometimes complain about, but it appears that breaker works against firewalls even though AP does not work against cover.