The very first thing you did is write a program that prints a pixel-perfect "memory reset successfully" message to the screen as if you had just cleared it yourself :)
better than making it seem like you had just done it yourself, you could use the Menu() function to simulate all the menu navigation necessary to actually get to that screen!
funnily enough, jabbing all the buttons on the calculator and having to select functions via menu listings created one of the comfiest development environments I've ever used. after a while, banging out a screensaver or fake menu became second nature.
Add a cryptic name, blank screen on start with a short timeout to return to menu when a key combination is not pressed and nobody will ever notice.