You do updates with SD card. To register all you have to do is go to Humminbird web site and have your ser num handy. Yes you can use a map card with out link and if your lakes are covered it is very helpful. So much so you will wonder how you got by without it. Remember this, your unit takes a micro SD card. When you buy one the micro will be in stalled in a full size adapter. Just remove the micro and installing unit. Don't loose the adapter incase you ever wanted to use in larger unit.