Voldemort isn't that good a coder - It's a continually updating system, that loads his present mindstate onto the entire system.. And he just rekeyed it to Hermione. All backups and lore: Gone.

Dumbledore loaded the cloak with Bhals stupefication, didn't he? Some delivery mechanism that only tiggered when worn by an adult. Hence the mad cackling and very poor plan for stopping Harry from breaking the universe <,<