Backup a GBA Pokemon bootleg save file

GBA Pokemon bootlegs save file are located in the rom itself.
In order to transfer to another official catridge or into any emulator we need to do some work.

What do we need:

- NDS Fat or NDS Lite (needs a working Slot-2)
- NDS FlashCart that can run Homebrew (R4 is the one used here)
- Pokemon bootleg game (Fire Red and Emerald are used here)
- GBA Backup Tool
- This software : GBA_Pokemon_bootleg_save_extractor.exe

Step 1
Extract the archive and copy the content of the GBA_Backup_Tool folder at the root of your NDS Flashcart.

(Optional)

Spoiler: Gaining time and sapce

If you want to reduce the size of the dump you can edit the GBA_Backup_Tool.ini file.
This example reduce the size of the dump to 16 MB, wich is the original size. This can help you save place if you want to do multiple backup.

Code:

# GBA_Backup_Tool.ini

FileDir       /GBA_Backup   ! Directory

SaveFile   128       ! 0:auto, nnn:Save File Size(KB)

RomSize       16       ! 0:auto, nn:Rom Backup Size(MB)

#Trim               ! Use Trim

ATTENTION !
The roms tested store the save twice. One time in the first half part of the rom and another time in the second half. In this case we can reduce the size of the rom by half.
Other cartridges may store save data at the end of the rom. Be carefull, you may end up skipping the save data part and be unable to extract it.
So reduce the size only if you know what you are doing.

Step 2
Insert your Flashcart and your GBA game into your NDS.
Power it on and launch GBA Backup Tool.

Press (A) to confirm that the gba cartridge is inserted.
Then press (R) two times to switch to Rom Backup.
Press (B) to start the backup, then (A) again to confirm.
Wait until the end. You can press (Start) to shut down your device once it's finished.

Step 3 (Updated)
The extraction of the save file is now simplified. You just need to use the given software.
Just click on the Load Rom button then specify the path to the ROM.
The software creates a save file with the same name of the given ROM and its path is written.

You can now use your save file where you want.
Have fun training your pokemon !

 

I found the reference online. So here is a picture of the PCB.



This model uses SRAM instead of Flash.
I will work soon on the same PCB that contain the Emerald version.

(I don't own the right for the image)

 

So after some research I found out this:
The best way I found to locate the save file in the rom is to search 4 specific bytes.

The first byte will be located at the adress: 0x****18
So we need to find the unknown *.

For that the software start searching at the last adress of the rom plus 0x18. Then it checks if the 4 next bytes are the one needed: 0x25 0x20 0x01 0x08.
If they not match it decreases by 0x20 the next first byte's adress to test.
When the last adress of the save file is located. It extracts the save file depending on the number of byte of the save file of the game.

It's also important to add stuffing bytes to respect the save file format and length.
It works without stuffing bytes in a save editor but emulator may tell the save is corrupted or give a black screen.

This is what I found for bootlegs I know. It mays be diffrents in others.

If someone wants to try it feel free to give me feedbacks.