Author Topic: Playing FFVII with a modified KERNEL on a PSP  (Read 7792 times)

Armorvil

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Playing FFVII with a modified KERNEL on a PSP
« on: 2009-04-22 19:53:26 »
It is quite weird : playing a KERNEL-modified PSX FFVII on an emulator (such as EPSXE) or an actual Playstation poses no problem ; but a KERNEL-modified PSX FFVII turned into a PSP EBOOT file makes the game crash when it tries to load some parts of said KERNEL.

Allow me to be more precise. I modified some parts of KERNEL.BIN into my FFVII iso. And when I turned this FFVII ISO into a PSP readable format, the game works fine until it tries to read some parts of KERNEL.BIN, such as the initial data, the characters' stats, or the equipment stats.
So, the "SQUARESOFT" brand appears as normal, I can choose New Game, but when I do, since the game tries to load the Characters' Initial Data (as well as the SCENE.BIN Look-Up data among other things) stored into KERNEL.BIN, it crashes (black screen of death, then the PSP shuts down).

And if I try to load a saved game, it works until I try press Triangle to open the menu. My guess is that the game tries to read the parts of the KERNEL that store the equipment and stat values or something, and since they're not exactly what they used to be (I modified a lot of things in this KERNEL.BIN of mine), it crashes too.

I repeat : starting a new game with this KERNEL on a PSX emulator or on a Playstation console works fine, though. So my guess is the problem doesn't lie with the ISO or the game data itself, but with the PSX to EBOOT conversion, or with what the PSP expects from an EBOOT file.

Any insight on this matter ? I just tried to make a single-disk EBOOT, instead of a multi-disk one, and the problem is still there (well, not exactly actually : the game still crashes when I try to go into the equipment menu or if I try to enter battle mode, but starting a New Game works fine).
« Last Edit: 2009-04-22 20:46:42 by Armorvil »

nfitc1

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Re: Playing FFVII with a modified KERNEL on a PSP
« Reply #1 on: 2009-04-23 04:46:55 »
From my experience with the PC version (so take this for what it's worth), every bit of the KERNEL.BIN is loaded into active memory when the game loads. By the time you get to the "New Game"/"Continue" screen it's all been loaded. If New Game is crashing then it's likely an error with the initial data somehow. If it crashes going into a menu, then you've likely got a text pointer out of place somewhere or the text is just too long for the game's memory to handle. I don't know the maximum size per string, but it's probably around 32 characters. What all did you change in the KERNEL and are you sure you packed it in correctly?

Armorvil

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Re: Playing FFVII with a modified KERNEL on a PSP
« Reply #2 on: 2009-04-23 11:01:41 »
From my experience with the PC version (so take this for what it's worth), every bit of the KERNEL.BIN is loaded into active memory when the game loads. By the time you get to the "New Game"/"Continue" screen it's all been loaded. If New Game is crashing then it's likely an error with the initial data somehow. If it crashes going into a menu, then you've likely got a text pointer out of place somewhere or the text is just too long for the game's memory to handle. I don't know the maximum size per string, but it's probably around 32 characters. What all did you change in the KERNEL and are you sure you packed it in correctly?

Yeah, I'm sure. The proof is, it works both on a PSX emulator and on a console. This is a PSP-only problem, and it doesn't make much sense to me. Thank you very much for trying to help, though  :-)

MrAdults

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Re: Playing FFVII with a modified KERNEL on a PSP
« Reply #3 on: 2009-04-23 11:50:01 »
Does the game load fine as an eboot if you attempt to inject an unmodified kernel.bin into the iso (before converting), using the same method you use to inject your modified one? If the answer is yes, then it's pretty much definite that it's your particular modification to the kernel.bin causing the problem. To that end, could be just about anything, but a likely candidate would be an out of range offset/value that is handled "gracefully" on real hardware/some emulators, but happens to probably cause a bad write somewhere on the PSP. However, if the answer to my first question is no, then you know where your problem is. :)

hotdog963al

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Re: Playing FFVII with a modified KERNEL on a PSP
« Reply #4 on: 2009-04-23 12:09:46 »
I've got this same problem, it is definitely the kernel.
I've tried replacing everything except for it, and the game functions perfectly, it's just when I add the custom kernel the battle swirl crashes and the equipment menu dies.

Although saying that, I have gone quite wild with the weapon names in places... but it doesn't explain why it doesn't work in popstation.

The Skillster

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Re: Playing FFVII with a modified KERNEL on a PSP
« Reply #5 on: 2009-04-23 13:50:14 »
Possibility is that the emulator can handle is gracefully, while POPS is designed to be like the original psx.

ignitz

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Re: Playing FFVII with a modified KERNEL on a PSP
« Reply #6 on: 2009-05-06 03:40:45 »
the size of all kernel must be pair and some other thing that I don't know

hotdog963al

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Re: Playing FFVII with a modified KERNEL on a PSP
« Reply #7 on: 2009-05-07 08:10:29 »
That could be the problem, mine is quite considerably smaller than the original!

Bosola

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Re: Playing FFVII with a modified KERNEL on a PSP
« Reply #8 on: 2010-06-02 20:44:30 »
NECRONECRONECRONECRONECRONECRONECRONECRONECRONECRO

Yes, it's a necropost. But I still haven't seen this question answered. I've heard gjoerulv and others refer to playing with a modified kernel on their PSP, yet so far I've no encountered an explanation on the forum. Searching yields nothing, and asking hasn't helped.

In absence of other information, I wonder if the issue is the KERNEL being padded with zeroes? Will editing YAMADA (using my thread's info) resolve this matter? Has any more research been done on this problem?

Gemini

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Re: Playing FFVII with a modified KERNEL on a PSP
« Reply #9 on: 2010-06-03 01:45:55 »
Funny. I've never had any problems with my modded KERNEL.BINs, nor on PC, PSP (4.01 here), or real hardware. If you say the game freezes when it tries to open a KERNEL segment, then it's an alignment problem. But then again, you say main menu freezes even tho that part doesn't have access to KERNEL strings or related data, at all; plus, it works on real hardware which makes it even more absurd because it has to work everywhere else if a grey Playstation doesn't complain. I say it's either the converter or your version of the emulator.