Install a map to GPSmap 421s via SD card

[flexit]

Hi Guys, im trying to complete the process of getting this map ([Only registered and activated users can see links. ]) unto my GPSmap 421. I purchased the map last week but i still havent arrived and we set sail tomorrow(

Thing is that a lot of explanations around the internet confuses me, and i fail at the first step which is to find the SD card ID.

I open the sd folder in my computer->tools->view->view hidden files and folder->view hidden systemfiles. Here i am SUPPOSED to find a file or folder named USBTRANS. But there´s no such file ( The card i use is a SanDisk Extreme 8 gb

Either way. One of the other steps i am concerned about is where i put in the MAP Id; How do i know what MapId is right for my chart?

another thing is that im supposed to put GPSMAPSUPP.UNL in a root folder, but the file i downloaded is a .IMG file.
I tried to open the .IMG file in notepad but i got an error message which claimed that the file is to big for notepad to open...

I know there´s a lot of tutorials out there but i found them all confused. If anyone can give me just a tiny bit of help, we would be forever grateful!

[p!xeldealer]

First of all the map that you have linked above as torrent is fairly old - you'd better take this: [Only registered and activated users can see links. ]

Second: forget SD card ID, MapID, gmapsupp.unl etc.!

You only have to unlock the downloaded img with unlocker like gimgunlock or unlocker alternative, which you can all find here in software section.

...may there always be one hand's breadth water beneath your keel