iMac 27-Inch 2013
To open the Mac you cut the tape holding the screen down as Apple decided to glue the screen in...
The ROM is a SOIC-8 chip (64Mbit) that can be read or written by the Medusa-3 with a Pomona clip.
The ROM in on the top (easy to reach) side of the motherboard.
The SPI connector is a Molex-30 but is not mounted by Apple.