This tutorial will teach you how to backup Nintendo DS save games from original game cartridges using an Nintendo 3DS. Using an Nintendo 3DS to backup Nintendo DS games is a lot easier than using an actual Nintendo DS.
You do not need to mess about with legacy WEP secured wireless networks, Firewalls, FTP's servers and GBA / DS flashcards. This is a simple offline solution anyone with a 3DS running the Homebrew Launcher or a Custom Firmware can use to backup Nintendo DS save games from original game cartridges in a matter of seconds.
Requirements:
You will either need a Nintendo 3DS running custom frimware or the Homebrew channel to follow this tutorial.
1. Getting started backing up your Nintendo DS game with the Nintendo 3DS:
First you need to download TWLSaveTool, this is the app we will use on the Nintendo 3DS for DS save game backup and restore.
2. Installing TWLSaveTool:
To install the CIA version:
Simply copy the TWLSaveTool.cia to the Nintendo 3DS sd card then install using your favorite CIA manager, I personally use BigBlueBox.
To install the 3DS version:
Simply copy the TWLSaveTool folder to your SD Card > 3ds folder
3. Backing Up Nintendo DS save games:
This is the easy bit, either load TWLSaveTool from the 3DS home screen if your using Custom Firmware:

Or from the Homebrew Launcher depedning on which version of TWLSaveTool you installed:

TWLSaveTool should display the DS game currently in your 3DS:

You can then press:
B - To backup the Nintendo DS save
A - To restore the Nintendo DS save
X - To erase the Nintendo DS save from the game cartridge
Start - exit the app
Y - To re start the app and backup / restore from a different game cartridge
Left / Right - allow you to change the file name of the savegame you are backing up (adds a number to the end of the save)
Backed up save games will be on the 3DS's SD Card inside the TWLSaveTool folder:

If you downloaded a save game from the internet you wish to restore to your original NDS cartridge simply name it what TWLSaveTool identifies the game title is, then add a number at the end.
For example POKEMON W.0.sav
Red = Game title as displayed in TWLSaveTool
Blue = File name, can just be .0 if you dont have any other saves for that game on the 3DS's SD card.
Green = File extension should be .sav
Congratulations you can now backup / restore Nintendo DS games in less than 20 seconds!
You do not need to mess about with legacy WEP secured wireless networks, Firewalls, FTP's servers and GBA / DS flashcards. This is a simple offline solution anyone with a 3DS running the Homebrew Launcher or a Custom Firmware can use to backup Nintendo DS save games from original game cartridges in a matter of seconds.
Requirements:
You will either need a Nintendo 3DS running custom frimware or the Homebrew channel to follow this tutorial.
1. Getting started backing up your Nintendo DS game with the Nintendo 3DS:
First you need to download TWLSaveTool, this is the app we will use on the Nintendo 3DS for DS save game backup and restore.
- If you have a 3DS running custom firmware you can use the CIA version.
- If you have a 3DS which only has the Homebrew Launcher you require the 3DSX version. Please note the 3dsx version requires you to have either PokéTransporter or Pokémon Dream Radar installed on your 3DS. In both cases you'll need to pay to be able to download them from the Nintendo Eshop.
2. Installing TWLSaveTool:
To install the CIA version:
Simply copy the TWLSaveTool.cia to the Nintendo 3DS sd card then install using your favorite CIA manager, I personally use BigBlueBox.
To install the 3DS version:
Simply copy the TWLSaveTool folder to your SD Card > 3ds folder
3. Backing Up Nintendo DS save games:
This is the easy bit, either load TWLSaveTool from the 3DS home screen if your using Custom Firmware:

Or from the Homebrew Launcher depedning on which version of TWLSaveTool you installed:

TWLSaveTool should display the DS game currently in your 3DS:
You can then press:
B - To backup the Nintendo DS save
A - To restore the Nintendo DS save
X - To erase the Nintendo DS save from the game cartridge
Start - exit the app
Y - To re start the app and backup / restore from a different game cartridge
Left / Right - allow you to change the file name of the savegame you are backing up (adds a number to the end of the save)
Backed up save games will be on the 3DS's SD Card inside the TWLSaveTool folder:
If you downloaded a save game from the internet you wish to restore to your original NDS cartridge simply name it what TWLSaveTool identifies the game title is, then add a number at the end.
For example POKEMON W.0.sav
Red = Game title as displayed in TWLSaveTool
Blue = File name, can just be .0 if you dont have any other saves for that game on the 3DS's SD card.
Green = File extension should be .sav
Congratulations you can now backup / restore Nintendo DS games in less than 20 seconds!
)
(so i did that a while ago)