how do i reinject a new save into the rom of a repro cart?

[Dr_Dankenstein]

hey all,
so yeah I basically have my old repros sitting around decided id dump the save as ive been playing emeral and lead green recently again,
I managed by using a gbxcart pro to get to the save by dumping the rom and using a save extractor tool which works in pkhex and I have made the changes to the save,
just wondering now how to inject the save back into the rom so I can rewrite it to the card?

I have used my gbxcart to write roms and such before anyways so writing it back wont be a problem its just the putting the modified save back into the rom I have no idea how to go about it


Any suggestions?

 

[hippy dave]

You'd have to write it back to the same location in the rom file as the previous save was extracted from. What save extractor tool did you use? Maybe it has the location info. If not, you could open the original save in a hex editor if you still have it, and open the rom file in the hex editor, and search the rom to find the matching save data, then overwrite it with the new save data.

 

[Dr_Dankenstein]

You'd have to write it back to the same location in the rom file as the previous save was extracted from. What save extractor tool did you use? Maybe it has the location info. If not, you could open the original save in a hex editor if you still have it, and open the rom file in the hex editor, and search the rom to find the matching save data, then overwrite it with the new save data.

https://projectpokemon.org/home/files/file/4104-save-extractor-from-bootleg-pokémon-gba-games/
thats the one that I used to extract the save from the rom, i did notice the title for the extracted save seems to have this on the end 0xFC0000

not sure if that would be where it starts or ends or even if it is the save location, I did check HxD for that number 0xFC0000 and it did show some data but im lost with this sort of thing if im honest

 

[metroid maniac]

https://projectpokemon.org/home/files/file/4104-save-extractor-from-bootleg-pokémon-gba-games/
thats the one that I used to extract the save from the rom, i did notice the title for the extracted save seems to have this on the end 0xFC0000

not sure if that would be where it starts or ends or even if it is the save location, I did check HxD for that number 0xFC0000 and it did show some data but im lost with this sort of thing if im honest

FC0000 is a common offset for save data in batteryless Pokémon bootlegs so you're on the right track. Your save file should be 128KB meaning if you overwrite starting from that offset it will end at FDFFFF

 

[Dr_Dankenstein]

ah thanks so if i open the rom on one side and the save on the other I should be able to copy the data from the save file into the rom starting at FC0000 and that shoould do it then yeah?

 

[metroid maniac]

ah thanks so if i open the rom on one side and the save on the other I should be able to copy the data from the save file into the rom starting at FC0000 and that shoould do it then yeah?

yes, overwrite don't insert (filesize stays the same)

 

[Dr_Dankenstein]

cool thanks il give it a whirl

 

[wilvic]

You can use this injector:

(It's an image because the system won't allow me to post the link)

I have tested this with a bootleg EMERALD and a save file from a legit cart.