PSP .VMP Header - Checksum

[Jedimark]

Does anyone know much about the PSP save file format. In particular the header which appears to contain a 160bit checksum (SHA1??) which prevents you from modifying the data (PSP just re-formats the memory card). I wanted to adapt Jenova to edit FF7 save games created on the PSP.

[Bosola]

Well, for a start, you should move to working with Black Choco rather than Jenova - it's newer, and also open source.

I know very little about the PSP save format. If the header looks like a SHA1 checksum to you, I'll take your word for it. You could always try to find an SHA hash generator, pipe in the data block, and see if it matches.

[Jedimark]

Well I'm only guessing SHA1 because its 160-bit but who knows. The main problem is working out what bytes are used to calculate the checksum because it's certainly not all of them.

[sithlord48]

PSP saves are on our todo list, but i have been lazy about doing so.Mainly because i don't have a psp to test with. your more then welcome to hack w/ us on black chocobo,  you might want to start by checking out the exsisting code over on the SVN portion of the webpage (http://blackchocobo.sourceforge.net). in order to hack w/ us you will need to know C++. also we use Qt, so knowlege of that may be helpful (but its not required since its a Framework that uses C++)

[Jedimark]

Very nice program, don't visit these forums very much these days but nice to see the community still going strong.
If you PM me your email address I can email you a VMP file to play with if you like.