This is the final part 4 in my series on Getting Rid of My MacBook — essential information that's hard to find!
After securely erasing the SSD and resetting the Firmware Password you're ready to put the final touch on your Mac: reset it to factory state by loading the operating system:
If you see the lock prompting you to enter the Firmware Password, go back to reset the Firmware Password.
Instead you should see the prompt to connect to your WiFi network.


When the new owner turns on the Mac, it will come up again to this dialog, and they'll be able to set up the Mac as if it came out of the box. Nevertheless, you may want to point them to my follow-up post "Hello Mac: What to Do First when You Receive a Used MacBook" to help them get the set-up right from the start.