Bought have 16GB RAM for Macbook Pro 13-inch (2012). The change was simple. Screw the bottom plate with PicoFinish Phillips Schraubendreher.261 PF PH 00x4 solved. 16 GB were detected without problems, though Apple says only a maximum of 8GB are allowed. Had with the built Hynix 2x2GB no memory problems Only with VMWare Fusion of total memory was then addressed