Great guide. I wanted to upgrade my late 2012 as much as I could to accommodate my large iTunes library. So with a little bit of cutting on the rubber hard drive cushion, I put a 15mm 5 TB hard drive and replaced the 120GB blade SSD with OWC’s 1 TB blade SSD. Now have 5.95 TB of fast usable space with my fusion drive.

4 longer screws on bottom