This guide has you removing 10 screws that you didn’t need to remove and tells you to disconnect the BD-ROM drive which according to *the* person in the scene you should never do.
Skip this step. The board remaining attached does not hinder removal or reinstallation of the HDD.
Only Remove the bottom left 4 screws holding the HDD caddy.
DO NOT DO
**Special Note** If you’re going to replace the hard drive, make sure that you disable Fast Boot and change to energy saving. Always go to the settings menu, go to Power & startup, and do a power down from here when possible. This will prevent E102 errors when the new drive is installed.
Incase you haven't read Chipwork's update, M7 is actually labeled NXP LPC18A1 that is located above the A7 in the middle of all the connectors