As above - its annoying needing to keep a spare arma helm just for this reason. Precedent is already set with avernic etc which is eligible for the d defender and bowfa being eligible for crystal bow step.
#Make Masori helm (f) eligible for the arma helm Falo step.
granite ridge
hollow jacinth
You could in theory fortify a masori helm without getting arma helm by breaking down other arma pieces to fortify a base masori helm. Sure, it is annoying to keep extra range helm in bank, but that is the reasoning behind it
granite ridge
ok then, make it possible if you have an arma helm on col log and use masori mask (f)