NOTE: The following will require you to edit game files, so make back-ups before proceeding.

This hack only allows you to unlock all dig sites on islands you haven't explored. If you've landed on any island and started digging, that island is excluded from this hack. Locate FslHunt.ini in your drive letter:jpogdata directory. Open the file using a text editor (like Notepad) and search for the line maxchosen. Set that value to 9. Save the file with an .ini extension