[brudgers]

Close access includes the assembly line, and that would be the preferred option for an intelligence organ seeking access to a consumer device - it scales well. Given the logistics of the electronics industry, there are many potential vectors to introduce the exploit unilaterally, though working cooperatively with Korean or Taiwanese agencies is possible given shared interests and those country's roles in component manufacturing. Of course with their own chip design arm, going directly through Apple is a more obvious choice.