Modifying NVRAM

CD-i Emulator is the first fully evolving windows compatible emulator project of the Philips CD-i system. Discuss the emulator, compatibility issues, seek help and support to get the program operating and post what you'd like to see in future revisions of the program. CD-i players ROM (BIOS) requests, begging and links will not be tolerated. Otherwise feel free to post your thoughts on this amazing new piece of software.
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Kao
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Modifying NVRAM

Post by Kao » Sat Oct 01, 2005 8:38 am

Hey, I'm trying to use a hex editor to modify values in my cdi205a.nvr file. I'm hoping to tweak the file and give my saved character a little boost ;) I'm almost certain I've located the values I'm looking for, but I have found that changing even just a single byte in the NVRAM from what it was saved as causes my saved game to no longer register. Reverting the changed value to its original state brings my saved game back without a problem. Any idea why I can't change the values in the NVRAM?

Edit:
I have found that by increasing one value but decreasing another value by the same amount allows the saved game to function. There must be some sort of cheksum business going on... Can any of you CD-I gurus help enlighten me here?
It's like 1993 all over again!
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cdifan
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Post by cdifan » Sat Oct 01, 2005 2:27 pm

There is no checksum built into the CD-i player or the emulator; this must be something that the CD-i title added itself, perhaps to foil attempts like yours... Of course, it could also be data integrity!

Which title are we talking about?

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Kao
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Post by Kao » Sun Oct 02, 2005 8:45 am

Both Zelda - Wand Of Gamelon and Link - Faces of Evil seem to check to make sure that everything adds up before accepting the data in the NVRAM as being a valid saved game. These are the only titles I have encountered with this sort of check.

I managed to work with it, though. ;)
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Korschan
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Post by Korschan » Tue Dec 23, 2008 12:49 am

Kao wrote:Both Zelda - Wand Of Gamelon and Link - Faces of Evil seem to check to make sure that everything adds up before accepting the data in the NVRAM as being a valid saved game. These are the only titles I have encountered with this sort of check.

I managed to work with it, though. ;)
How did you do that? I also changed the data of the nvram-file but it doesnt work. What have I to do to get it working?

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