Im not sure what you mean by "open a terminal window" and I certainly don't know what the correct path on the card is or where I use it!
drag the icon of gimgunlock to the Terminal window
drag the icon of img file of map to the Terminal window
hit return to run.
Not so hard
path is the one Neil gave you at point 6 in post n 8.
If you cant do these simple steps, download an already unlocked map or buy it
Bookmarks