Playstation cracks and emulation

[mrgone]

Ages ago i had a game for the PS1 which needed a crack against copy protection and an optional trainer was also available.
Both where applied and worked in unison:
It worked on my original chipped PSX and i played the same ISO on my PSP as a PSXPSP.
Recently i tried to play it on RetroArch and the game hung on the point in the intro where the copy protection took over.
I researched and was able to fix that with a sbi file.

But i don't understand why this was neccessary?
The crack worked and skipped the CP but retroarch ignored that?

Can anyone enlighten me why?
I dont need technical details or source code references but a simple explanation would be nice
Is there a secret Retroarch option to "ignore CP cracks" ?

 

[KleinesSinchen]

Interesting topic!

First of all: I have no real answer (but some questions).
What game is causing the trouble?

Some of these cracks/crack-intro things don't seem to really work under circumstances not anticipated when they came out. For example I ran into LibCrypt crashing "Crash Team Racing" on a cracked copy when booting the CD-R when FreePSXBoot came out.
Using a modchipped console the game works fine, but LibCrypt crashes the game like on an unmodified (bad, incomplete) copy despite the crack with the software exploit. Why!?

That brings me to the next question: Is applying a patch even needed for an emulator? I don't use PS1 emulation and don't know if subchannel data is properly presented to the game. Normally dumping original CDs with RAW+Sub96 should suffice to make LibCrypt games work without patches (given the emulator provides the subchannel data). Same for burning RAW-DAO+Sub96 -- games should work unpatched on modchipped consoles.

This might be an option for patching games:
https://alex-free.github.io/libcrypt-patcher/

 

[mrgone]

patched games suddenly crashing on newer exploits is a great example.

why to use a classic crack in these days:
i had the patched iso readily available, and also both trainer and crack had nice chiptune music - i like that

for the other question: no, the crack is not needed for retroarch if one has the sbi file

regarding modchipped consoles: depends on the chip, my chip is one of the earlier ones, so extra cracks were needed at that time

 

[Fien]

Some modern emulators seem to have problems with some patched games.

I have this version of Crash Bash (https://hiddenpalace.org/Crash_Bash_(Oct_9,_2000_prototype)) on a pressed bootleg disc with has a PAL/NTSC selector. It plays fine on real consoles and old emulators like ePSXe en PCSX-R. But crashes on Duckstation or the PS1-mode of a PS3.

 

[mrgone]

Interesting topic!

First of all: I have no real answer (but some questions).
What game is causing the trouble?

Some of these cracks/crack-intro things don't seem to really work under circumstances not anticipated when they came out. For example I ran into LibCrypt crashing "Crash Team Racing" on a cracked copy when booting the CD-R when FreePSXBoot came out.
Using a modchipped console the game works fine, but LibCrypt crashes the game like on an unmodified (bad, incomplete) copy despite the crack with the software exploit. Why!?

That brings me to the next question: Is applying a patch even needed for an emulator? I don't use PS1 emulation and don't know if subchannel data is properly presented to the game. Normally dumping original CDs with RAW+Sub96 should suffice to make LibCrypt games work without patches (given the emulator provides the subchannel data). Same for burning RAW-DAO+Sub96 -- games should work unpatched on modchipped consoles.

This might be an option for patching games:
https://alex-free.github.io/libcrypt-patcher/

ups, i overlooked the question for the game: it was the german version of dino crisis 1
cracktro patch by kaiisto and pal/ntsc selector by paradoc

 

[esmith13]

I don't have a factually proven answer but I have what I believe is the reason for your experience.

The crack/trainer was used to prevent older modchip detection on real hardware. The reason this was ever needed was because older modchips would constantly broadcast that the "wobble detection" on the disc has passed, from the moment the console was powered on until it was powered off so no matter when the console looked for that signal it was there and ready. Games like the one you're working with had anti-modchip code that would not only look for the passing signal when actually needed but also at other times when the laser wasn't actually in a position to read the wobble. If the game got the passing signal when it shouldn't be able to, the game code would know you had one of these old dumb chips and halt the game with the "modchip detected" error.

Now with emulation in retroarch and I'm sure some other emulators as well, they deal with these games that need a reproduction of real "wobble detection" via the .sbi file which I assume is a dump on that portion of the disc, previously unobtainable back then. I am assuming that your issue lies with the crack/trainer patching out the modchip detection code making retroarch not able to detect that this game needs to have the matching .sbi file read at all - be it because modifying the game image has made it impossible for Retroarch to know what this game is or possibly because the RA core's code actively looks for what you've patched out to know when to read the .sbi file.

Bottom line in my thought is - either patching the ROM (which would alter the CRC/MD5 hash) prevents RA from knowing it's a game that needs to use a .sbi file so so the .sbi file is ignored, or patching the ROM has [intentionally] removed the code that the PS1 RA core looks for to trigger reading the .sbi file at the right time to satisfy the request.

Again, I have no proof that this is what's happening, but to me it seems logical if you think about what the emulator is trying to accomplish vs what the crack/trainer was intended to accomplish.