With the A6, the secure area is in the Boot ROM's Silicon. . . it was not yet named the Secure Enclave. There was also a section of the A6 processor which was walled off, not as secure as it would be later with the Secure Enclave, but if foreshadowed what was coming. iOS 9 takes advantage of those when running on the A6.
OK that is really confusing to come into and try to understand from the outside. I suggest employing precision in discussion. If we mention Secure Enclave, perhaps it would be best if we adhere to the formal technical definition of it in the sense that it runs in its own little processor component on the A7 and possibly beyond, but not the A6 which the iphone 5C in question uses. It sounds to me as if the iphone 5c from the snippets of definition I have seen floating around, by contrast, use some kind of EEPROM boot rom library security related routines that provide conceptually similar (though less secure in the absolute sense) security at some higher functional level. Does that make any sense? If not, I wonder where I might have strayed. If something like this is spelled out in each response (I know it is somewhat more lengthy) then perhaps folks will be less likely to go down semantic rabbit holes in discussions. Then someone can come in during the discussion and still understand it without having to learn thread specific shorthand that does not apply outside the thread (eg in the so called real world, for example). All standard disclaimers remain applicable. If I am babbling on, apologies to all.