i had this doubts before too
1st of all you'll need the following things:
Slot-1 DS FlashCart ( can be any, if its one from M3 Adapter, AKA : M3 DS Simply, M3 DS Real or M3i Zero, you'll need the V0.01 of Rudolph GBA Backup Tool)
Real GameCart
Computer (Duh?)
So its basically this:
Dumping:
To dump the rom, run Rudolph's GBA Backup Tool V0.01 on your NDS via the flashcart ( or last version if not using a M3 Adaptar Flashcart )
You'll have a menu, and on bottom screen, you'll have the commands.
Press R twice, to get to the Rom Dump
Press B to back up the rom.
A message saying "File Name : ROM NAME.gba The file is made by this file name. (A):Run, (B) : Cancel
Press A and a bar should appear filling up ( from 0% to 100% ) when it ends, the rom has been dumped
Dumping Save:
Run Rudolph's GBA Backup Tool
The 1st menu should be: Save Backup
Press B (New SAV file create)
Message Saying: File Name "SAV NAME.sav" The file is made by this file name. (A): Run, (B) : Cancel
Press A
A loading bar will appear (from 0% to 100%)
When the bar finishes filling, the sav has been dumped.
Restoring Save:
Run Rudolph's GBA Backup Tool
1st of all make atleast 1 backup of your current save
-At this point you must have the save file that you want to upload to the real gba flashcart
From the 1st menu, press R once to get to the Save Restore menu.
Now, press B to get the SAVE area of rom initialized
After that select the save file you want to upload to the cart on the TOP SCREEN (HIGHLIGHTING IT)
Press A to restore the save data to the cart from the SAV file selected on the top screen
Restart DS and play gba rom to check if it worked
IF YOU STILL HAVE ANY DOUBTS ABOUT THIS, feel free to say it here i'll be glad to help you
(tutorial made by me, just now, looking at my ds xD)