dic:hardreset seems to be a reference to the already mentioned factory reset.
A factory reset will delete user data and Apps, and the (untouched) OS will then start with the initial user setup again.
If you want or need to go a step further, you can wipe the phone and install it from scratch … 🇬🇧 🇩🇪 ✏ Installing the Fairphone 2 from scratch in case of failure / Komplette Neuinstallation des Fairphone 2 im Fehlerfall.