[PSP] How do I recompile a modded game back into a functional ISO?

[Ajbjc]

So I used UMDGen to unpack the .iso file for Burnout Legends (the platinum edition specifically, if that makes any difference) and decided to make the following two changes:

• Change the music files based mostly on this method: https://gamefaqs.gamespot.com/boards/921495-burnout-legends/49099963; though the main difference being converting the .mp3 files to .at3 rather than .toc
• Update the car audio files (.lwd and .hwd) using this video as a guide https://www.youtube.com/watch?v=QbhbrP3zf3k though took some cross-referencing with the video to find where the files were and what hex-editing software to use

From what I saw about the game was I just put all the files back into UMDGen, put in the correct disc name under UMD Properties, save as an .iso and move to either my PSP or PPSSPP. However, it doesn't work, neither recognise it as a valid .iso and I don't know what else I'm meant to be doing.

The file structure of the .iso is:
UMD_DATA.bin
PSP_GAME
-SYSDIR
--UPDATE
--BOOT.bin
--EBOOT.bin
-USRDIR
--amodule (contains two more folders, both of which are .prx files that do something
--data (mostly .bin files for Global and Head files, and other files)
--music (contains 21 .mus files which are just renamed .at3 files)
--ovid (contains a bunch of different .at3, .pmf and .m2v files)
--phev (contains folders with all the vehcile data, with the .lwd and .hwd files I edited, and a .bin file for the vehicle list - vlist.bin)
--sound (just sound effects)
--tracks (contains folders for all the track data, and a .bin file for the track list)
-ICON0.png
-ICON1.smf
-PARAM.sfo
-PIC1.png

I don't know if I need to do anything with changing the music, as I deleted the files and replaced them with different files of the same names and I don't know what they're linked to. As for the vehicle sound changes, I'm not sure what I need to do, if anything, to the .bin file.

As for the vlist.bin file I don't know how to access the files within it, MagicISO and UltraISO are both unable to convert it to an .iso.

[[Unknown]]

Generally, I'd expect reconstructing the ISO like that to work.

That said, UMDGen allows you to open an ISO and replace files within it.  That's probably the more foolproof way, since you only changed a chunk of files and not everything.

If PPSSPP says something isn't a valid ISO, it most likely means the files aren't in the right places.  The structure you described sounds right, so I'm not sure why that'd be.

Basically it's just looking for ISO 9660 format with Joliet extensions.  The file should be an even multiple of 2048 bytes long, should start with a bunch of NUL bytes, should have "CD001" at offset 0x8001 within it, and should have "PSP GAME" at offset 0x8008 within it.

EBOOT.BIN should actually be uppercase, and case matters.  EBOOT.bin would not work.  If you weren't using lowercase just from retyping it, that may be the cause.  Files should have exactly the same names as they did before - case and everything.

-[Unknown]

[Ajbjc]

[/size]
If PPSSPP says something isn't a valid ISO, it most likely means the files aren't in the right places.  The structure you described sounds right, so I'm not sure why that'd be.

The file structure is what the problem was, and it was something I didn't think would affect it and didn't think would've been too important to the file structure I gave. First time putting together a hack, like I mentioned in the original post, I'm going by simple guides and YouTube videos that I found. I had the PSP_GAME folder and UMD_DATA files within a folder called BURNOUT, can't if or why I did that as it was something I did a few months ago, though just found out recently that what I using that whole time was the original ISO and not the modded one. UMDGen said it didn't detect a UMD_DATA file which was odd but thought that it may be because I changed the files.


Taking a small break from that game I decided to mess around with another game, I noticed that this game had the two files on its own, and not in a folder, so I changed one of the at3 files as a test, put it back together and it worked. Went back to burnout, recompiled the files but this time without the extra folder containing everything, and it worked.

EBOOT.BIN should actually be uppercase, and case matters.  EBOOT.bin would not work.  If you weren't using lowercase just from retyping it, that may be the cause.  Files should have exactly the same names as they did before - case and everything.

Didn't know that, though most files, like EBOOT, do have their file extensions in upper case, it was more of personal preference when typing it out here.