MacBook Pro 'retina' 15-Inch
Retina 2012 / Early 2013
A1398 emc2512 / emc2673
To open the Mac you need a P5/PL4 Pentalobe screwdriver.
The motherboard number is on the lower left corner of the motherboard, on the topside of the board.
The ROM in on the top (easy to reach) side of the motherboard.
The ROM is a SOIC-8 chip (64Mbit).
To read or write the ROM use Medusa with A4056 (blue) EasyFlash adapter (arrow points to the back of the Mac).