In order to unlock this acheivement, you will need to have earned the Second Helping achievement, for having obtained your second ArFA-Sys part. In your house, open the ArFA-sys menu by talking to your ArFA-Sys and not sparking a cutscene. In this order, hit the commands.
Either you or ArFA-Sys
Head to the third section by hitting
2 times, and change the color. Make sure to hit
to save the changes. After that, the achievement will pop up.