[quote]The Halo 4: Essential Visual Guide states that his armour was fully updated by Cortana, and that it now resembles an earlier iteration of MKIV. Frankie acknowledges the use of nanotech on his armour by Cortana. Chief wears a "very fancy, very custom, very unique "Cortana special" armor".[/quote]This is all you need to know. Mmm, another thing worth noting, Halo 5 implies Mark VI Gen1 has limited nano-machine use for self repair.