No cached EPG data, try again later (database disk image is malformed)

There is a utility to clear the EPG data, but it requires the Humax to be in Maintenance mode, follow the link HERE, down to the 'epg - Clear persistent EPG data' option
The database in question is not the EPG data though. The former is derived from the latter. Clearing the latter won't fix the database (unless it also deletes it, but I can't be bothered to check at the moment).