[HELP] Modifying Savegame files

[NovaCaine]

Hey all,

Was wondering if anyone has been able to modify a PSP savegame file (mainly the PARAM.SFO file) successfully without it becoming corrupt?

I'm asking this because Im trying to create a track Manager for Gripshift and was wanting to move the data to a different folder.

Does anyone have any good links on how to go about doing this, does the savefiles use a checksum to determine if the file is ok? I'm kinda new to the homebrew scene and have tried searching the forums for an answer but couldn't find any helpful information.

Thanks

[jimparis]

Was wondering if anyone has been able to modify a PSP savegame file (mainly the PARAM.SFO file) successfully without it becoming corrupt?

Yes, the savedata/encrypt sample takes care of correcting the integrity hashes in PARAM.SFO.

[NovaCaine]

Thanks for that.

I did have a look at that, but it all looked really complicated to me. Noticed in the readme file it says

New saves require a
game-specific encryption key which can only be found inside the game
code.

How would I go about getting this code? Do I need to dump my UMD to get it? How would I go about changing the PARAMS.SFO file.

Sorry if these are noob questions, but I am a noob to this. Just wondering what I need to accomplish this and where to get it from.

Thanks Again

EDIT:
The files I currently have are
Gripshift Track save:
ICON0.PNG
ICON1.PMF
PARAM.SFO
TRACK.XDS

Gripshift Game Save:
ICON0.PNG
ICON1.PMF
PARAM.SFO
PIC1.PNG
PROFILE.XDS
SND0.AT3

Just from what I've read so far int he decrypt/encrypt source, would I be right to assume the .XDS files are the encrypted files I pass to the encrypt_file function? what is the pain text file need to be?

[jimparis]

How would I go about getting this code? Do I need to dump my UMD to get it?

Yes, you will have to disassemble the game and figure out what key it uses. If the game runs on 1.5, it's an old format save and you don't need a key. Old formats work with Shine's tool, too, which may be easier to use.

How would I go about changing the PARAMS.SFO file.

Decrypt the save data file (yes, probably *.XDS), then change your param.sfo however you'd like. When you reencrypt the save, it will correct the hashes in the SFO.

[NovaCaine]

Sweet. cheers for the good news.

One last question, after dumping the UMD I noticed that the BOOT.BIN file was about 3 megs and empty (every byte was 0). Is that normal?

[NovaCaine]

OK, ignore the above post. I've managed to move a save file to a different save slot fine.

But I am having trouble converting saves between regions, was wondering if anyone has had any experience with this? does the game key change between regions?

[sg57]

Hey say the game is like... 2.01+, would igo about hackign the gamesave via getting the dumped game, find some file inside it, (what name!!) then look for a key?

Daxter for an example.. I have my dumped game of it, now what? ive been poking and hexing fil,es lately and found squat... about aket

[Drakonite]

We don't hack official games here.

...I dunno how this thread lasted so long. Locked.