ndsi-savedumper VS nds-savegame-manager

First, follow dsi.cfw.guide to get homebrew setup on your DSi (you must install Unlaunch or it won't work). Then download DSi save manager and use that to dump your save file. Then you can move it to your PC via the SD Card

For DS (Requires flash cart)For DSi (requires Modding)For 3DS (Requires Modding)

Restore that edited save file to your game using savedumper.

Just to add to this, there's also ndsi-savedumper. It's no longer in active development, but you can get it here: https://github.com/edo9300/ndsi-savedumper

You can use a savedumper (https://github.com/edo9300/ndsi-savedumper) for dumping and injecting saves from and to legit cartridges. If you're playing a gba game on the DSi, you will have to install GBARunner2 (https://github.com/Gericom/GBARunner2) in order to run gba .rom files. I'd try placing your .sav file next to your .rom file and naming them like this: "{filename}.rom" and "{filename}.sav", where the {filename} part is identical.

ndsi-savedumper

DS Phat or Lite with a DS flashcart (or Action Replay DSi that takes a MicroSD though you also need ARDSI Menu to handle DLDI auto patching or track down the appropriate DLDI patch and patch the nds file for NDS Savegame Manager yourself), wifi your DS can connect to, an FTP server with write access accessible through that wifi, and NDS Savegame Manager. Does NOT work on DSi or 3DS since they turn off the cartridge slot if you're booted into a flashcart and then eject it. Use above CFW methods for those consoles. The FTP server can be any PC FTP server program, or a phone file manager app like Solid Explorer that includes a builtin FTP server function. The wifi can be a phone hotspot with no password. Copy the nds and ini files to the root of your flashcart's SD card, and edit the ini to have the correct IP, port, username and password for the FTP server. If the FTP server has anonymous (no password) access, put anonymous for the user and anything that looks like an email for the password ([email protected] for instance). There is also a pdf with some additional help that comes with NDS Savegame Manager. This method sucks because of complexity of setup, but at least a lot of people already have R4 cards. Avoid it if you can.

Try this: https://github.com/AdmiralCurtiss/nds-savegame-manager

This is the tool, though you'll need a DS flashcart to run it from. I know you'll need either a slot 2 device or wifi and any FTP server program to backup saves. I'm not sure whether it can restore them without this from the flashcart's SD though.

For DS (Requires flash cart)For DSi (requires Modding)For 3DS (Requires Modding)

on DS you have this tool available, but I haven't personally used it so can't say much about it beyond that I've seen it recommended multiple times and it seems to work for people: https://github.com/AdmiralCurtiss/nds-savegame-manager

You can use a flashcart and homebrew. Here is an example: https://github.com/AdmiralCurtiss/nds-savegame-manager

You need to purchase an R4 flashcard and then put thisNDS Savegame Manager on it. Then you can dump your retail save to the SD card in the R4. Then make backups of your save in the cloud or wherever you prefer.

There's also a DS app called Savegame Manager but you need either an original DS or DS Lite and a DS flashcart to use it.

If you can't get GBA Backup Tool to work you can try Savegame Manager. Hopefully that works a bit better for ya.

To manage your save file for Emerald and FireRed, use the DS homebrew DS Savegame Manager. It will also work for save games for all GBA and DS games.