I discussed this with Garmin support asking if I backup the deleted maps, if it is possible to install them back later on. They said it would not be guaranteed and if not, you need to buy them if you need them. My question would be, if you tried to put them back and if it worked :)The most important thing you can do before starting anything like this on a Garmin device that you may want to put back to factory clean state is, backup.