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Author Topic: Question Regarding PS1 ROM Hacking  (Read 1143 times)

fantasticfox

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Question Regarding PS1 ROM Hacking
« on: November 22, 2021, 10:20:39 am »
Hi, I'm pretty new to rom hacking and have been cutting my teeth on a SNES game.  My goal is to translate a PS1 game and I'm wondering, if I extract the PSX.EXE from a .bin using jPSXdec, can I just edit the hex and replace it using Daemon Tools or is there extra stuff I need to be aware of?  Like, should I extract raw or normal?

FAST6191

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Re: Question Regarding PS1 ROM Hacking
« Reply #1 on: November 22, 2021, 12:25:53 pm »
Some PS1 games will have checks on the binary (and maybe other files) as a type of anti piracy or maybe just self checking -- if you have ever read into editing saves then same idea but for the CD. You may have to either figure out what it does for that or dodge the check itself. Easy enough to check for this -- find the thing in the exe in the ISO, find a bit of text you want to edit, replace one character with another valid character (there is presumably another right next to it), save and load the game up, if it fails or triggers anti cheat/anti piracy then you have that to contend with, if not then you can further experiment with extraction and insertion methods using your tools of choice (daemon tools would not necessarily be my first choice, though it can probably get it done) and seeing if that breaks things on emulators or hardware.

Equally is the text you want to edit in the exe file? It is more than possible but part of the fun of having discs if you can load and unload data like text at will so the better devs would have had it as a separate file, though nobody in any way accomplished around here would say that devs always took the best path.

Beyond that then it is the same as the SNES or anything else really -- encoding, font issues, locations, markup, pointers, finding space to any extra you want to add, general translation issues, what your editorial policy is... you get to sort that.

fantasticfox

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Re: Question Regarding PS1 ROM Hacking
« Reply #2 on: November 22, 2021, 01:07:22 pm »
Thanks!  I tested just inserting the original PSX.EXE back into the .bin with cdmage and it worked!  So, next up is actually editing something.

MysticLord

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Re: Question Regarding PS1 ROM Hacking
« Reply #3 on: November 22, 2021, 06:16:55 pm »
What game, if you don't mind me asking?

Keep us posted if you need help.

gukid/ioev

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Re: Question Regarding PS1 ROM Hacking
« Reply #4 on: December 16, 2021, 01:19:53 pm »
Some PS1 games will have checks on the binary (and maybe other files) as a type of anti piracy or maybe just self checking -- if you have ever read into editing saves then same idea but for the CD. You may have to either figure out what it does for that or dodge the check itself. Easy enough to check for this -- find the thing in the exe in the ISO, find a bit of text you want to edit, replace one character with another valid character (there is presumably another right next to it), save and load the game up, if it fails or triggers anti cheat/anti piracy then you have that to contend with, if not then you can further experiment with extraction and insertion methods using your tools of choice (daemon tools would not necessarily be my first choice, though it can probably get it done) and seeing if that breaks things on emulators or hardware.

Equally is the text you want to edit in the exe file? It is more than possible but part of the fun of having discs if you can load and unload data like text at will so the better devs would have had it as a separate file, though nobody in any way accomplished around here would say that devs always took the best path.

Beyond that then it is the same as the SNES or anything else really -- encoding, font issues, locations, markup, pointers, finding space to any extra you want to add, general translation issues, what your editorial policy is... you get to sort that.

Just curious, what would you suggest instead of daemontools to extract/repack psone isos?  For some reason I remember a while ago there existed a tool that could extract to a folder, and then also repack all the files in the same order (which was important for some games) but I can't seem to find it now.

FAST6191

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Re: Question Regarding PS1 ROM Hacking
« Reply #5 on: December 16, 2021, 02:27:46 pm »
I don't know what people are suggesting for PS1 games, and did not know they suffered ordering issues with things (though it makes sense as I have seen devs in interviews mention file ordering on discs to get best speeds, and I presume there is some command to read file number [blah] rather than force a lookup first as it is obvious/exists on many things, not to mention the whole Square Enix raw LBA audio stuff).

For the most part I usually lead with one of the various "we extract/convert/make every format of iso" programs ( https://www.topbestalternatives.com/ultraiso/ https://alternativeto.net/software/magiciso/ ), not least of all if I am also using a Scene/legacy rip of a game* rather than my own, and most things I do tend to involve me manipulating single files with more in place (or existing free space) edits so can also do in place overwrites easily enough. They all tend to be about as good as each other, some might even have demo modes that allow insertion of files (most will limit rebuilds to 200 megs of something).

*for others playing along that might be more used to the modern Scene with nice standards and NFOs it would not be until somewhat into the PS2 lifetime that people paid attention to/really created rules on consoles, and many ripped their own (650 megs on dial up is painful) from rentals/borrowed. Most CD burning software of the time (Nero Burning ROM, clonecd, cdrwin and some others forming the top picks for most) all also unofficially competing in who could rip PS1 games the best meaning whoever updated their software first to be that bit "more accurate" for the purposes of things got those using it to make a rip.

For CD/iso9660 stuff there was some free software around that could build ISOs. Don't know of the PSP's UMDgen will do for PS1 stuff, and frankly I would go looking at what the PSP peeps for their injections for the emulators/backwards compatibility there.

Risae

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Re: Question Regarding PS1 ROM Hacking
« Reply #6 on: December 19, 2021, 04:32:32 am »
Just curious, what would you suggest instead of daemontools to extract/repack psone isos?  For some reason I remember a while ago there existed a tool that could extract to a folder, and then also repack all the files in the same order (which was important for some games) but I can't seem to find it now.

For PS1 ISOs i recommend

Dumping: https://github.com/Lameguy64/isodump
Rebuilding: https://github.com/Lameguy64/mkpsxiso