savhax requires some sort of extended ram (3in1, opera ram, etc etc etc).
Remember to select TYPE 3 and 512 KB!!!
Slot 1 Flashcart:
1. Go into your game, move around a bit and save. Move around a little more and save again.
2. Reboot your DS with your flashcart and start savhax.
3. Pull out your flashcart and insert your retail cart.
4. Select "EEPROM --> SRAM" and let it do its thing.
5. Check your SRAM hexdump, an make sure it looks garbled (lots of different values)
5b. If not goto 4.
6. Put your flashcart back in the DS, keep the power on! (IMPORTANT!)
7. Now VERY Quickly restart your DS (turn off and then back on)
8. Start savhax again.
9. Select "SRAM --> FILE"
10. Assuming it comes up with the correct size, you're done!

hai seguito le istruzioni?
l'hai avviato da SLOT 1 tenendo una slot 2 inserita?
hai impostato come nel readme?
dopo aver fatto il dump, hai tolto HG e inserito la flash e avviato l'homebrew?

sisi, ho anche provato più volte ma niente; forse la ram dell'm3 non compatibile...

EDIT: al 5° tentativo ci sono riuscito, mi sa che ero troppo lento io XD

uppo questo vecchio 3d per dire che girovagando per internet ho trovato Questo
però non riesco a capire come funzioni.. se qualcuno vuole cimentarsi nell'impresa direi che è ben accetto XD

1)First thing you need to do is setup an FTP server. I have my own private FTP server overseas but I imagine smallftp would work just as well. Verify that your server is working on an open port (usually 21) by connecting to it with a client like http://filezilla-project.org/. If you need specific help with what programs you should use and what you need to setup an FTP server it's quite easy to google as there are literally thousands of FTP servers out there. Although I hear for the purposes of save file backup smallftp is the best. Once you verify your server is running be it smallftp or whatever it is you use AND you've verified you can connect to your server move to step 2

2)Verify your NDS can connect to the internet normally go onto the official Nintendo GTS and setup your wifi connection in the wifi connection settings of your NDS. You will have to set it to your home network and verify your NDS is visible by your router on your home network. Once you verify your NDS can use your home network to go online AND you see it can access the official (Nintendo based) GTS and function normally move to step 3. Again if you have trouble with this the official Nintendo support website has instructions on how to get your DS working on your home connection.

3)Now we need to setup the save manager. I'm using an Acekard2i and copied over savegame_manager.ini and savegame_manager.nds to the root of my acekard. Now that you have these two files copied to the root of your acekard2i we need to modify the configuration settings to redirect our save files to our personal FTP server.

4) Crack open the savegame_manager.ini you just copied and that is in the same directory as your savegame_manager.nds and you'll see this:

Simple fill in as required
If you're running small ftp or some other home FTP client you need to redirect savegame manager to your home computer to do this you'll need your home computers IP address. This can be found by hitting start and in the search programs and files box or the run box typing cmd.exe

now that you have cmd.exe open type ipconfig and you will see the IP address of your home computer running the ftp server, it's usually something like 192.168.X.X

ftp_ip = ftp.myfakeftpaddress.com or (192.168.X.X ) < your ftp address
ftp_user = yourftppassword < Make you set the password in your FTP server to exactly what you set in your FTP server settings A good rule of thumb is that if you can login with filezilla with the exact username and password you type in here to your ftp server your savegame manager will too.
ftp_pass = yourftppassword
ftp_port = 21 < your ftp port again, if you can login with filezilla using this port so will savegame manger.

Save the file, close it and boot up your flashcard with the program copied over.

5) Run savegame manager.nds and press B at the start screen be sure not to have any GBA games in the slot below if you have an older DS.

6) We need to first obtain a copy of our save file so we hit backup game> .sav on the touchscreen.

7)It will instruct you to remove your flash card and insert your retail game when done hit A

8)If you setup steps 1-4 correctly it should only take 12 seconds or so to connect to your home FTP server. If you messed up steps 1-4 or something on your router and/or computer is blocking your ftp server or NDS you will get an error at this point. error list below

A)stuck at connecting to FTP... < your FTP server is not setup correctly see if you can connect to your FTP using programs on your computer
B)Stuck at connecting to AP< Your NDS cannot connect to your home connection see offical nintendo support as to why
c)Incorrect password< your ftp password is wrong

9)If all goes well you will notice three options A, select a savegame to overwrite already on your FTP server. B move one folder up in your FTP server or press L+R to create an entirely new copy of your retail HG/SS savegame on your FTP server, I recommend you use L+R. You will then see a progress bar and your savegame will begin to download to your FTP server folder.

10) Turn off your DS, your savegame is now on your PC!

11)Once edited savegames can return to your DS by repeating at step 7 and instead touching the restore .sav>game

12. Use your D padto select the save file you want to restore and hit A. Follow the same instructions.

Io sono riuscito a dumpare il save con questo homebrew via wi-fi; ho seguito la parte riguardante la configurazione del server di questa guida e poi le istruzioni a schermo dell'homebrew.
Se ti può interessare nel topic di projectpokèmon c'è questo post

Io la parte di configurazione dell'FTP l'ho fatta, si connette e tutto, ma quando cerco di salvare il sav di SoulSilver mi dice "Error: wrote 512, got x (numero variabile)", fermo al 2%. Qualcuno sa aiutarmi?

Io ho questa configurazione:
Nintendo DSi XL con firmware 1.4.1E
SuperCard DSTWO con firmware 1.09
Kingston SDHC 16Gb
Nintendo DSI XL configurata su Wifi by a router linksys
slot2 kingston 2GB memory card

Ho seguito le istruzioni legate al link http://www.gbarl.it/index.php?showtopic=62507 ma temo che siano datate in relazione alla NDSi XL.
Ho provato i seguenti tool ma nessuno ha funzionato.
NDS_Backup_Tool_FTPd
NDS_Backup_Tool_Wifi.nds
NDS_Backup_Tool_3in1.ini
Woodumper

Domande
1) C'e' qualcuno che avendo una configurazione simile e' riuscito a fare il dump/backup delle proprie ROM e puo' essere cosi' gentile da girarmi il link ad un tutorial funzionante?
2) Dove posso trovare il savegame_manager per NDSi XL che viene citato nel tutorial che ho quotato?

Grazie in anticipo per la disponibilità

Mi dispiace ma con DSi e DSi XL non si può dumpare. Dopo che il DSi(XL) avvia un gioco non permette più lo scambio di cartucce.

Ah, grazie a Sasuke Nintendo della segnalazione, sabato o domenica provo... anche se al 99% non ci riuscirò Sono negato per questi procedimenti.
Se ho capito bene la funzione Slot2 funziona solo con la EZ3in1, peccato che abbia solo M3SD e EZ4, dovrò farmi la procedura via Wi-Fi...
Non ho capito una cosa: questo tool permette solo il dump o anche il restore del save?