With the motherboard out of the way, we find ourselves short of parts. All we have left is a lonely little daughter board.

Home to the charging port, a closer examination of this daughter board reveals cables for the bottom buttons, as well as a smattering of ICs:

Cypress CY8C20075-24LKXI CapSense capacitive touch-sensing controller

RFMD RF1119 antenna controller

S1221 primary microphone