GOALS.md

Goals

This project wants the data in Let's Make a Soccer Team! (SLES_541.51) to be easy to change, so that anyone can build a modded version of the game: a different starting season, real names, a harder economy, fixed bugs. The end product is a set of GUI tools that change the game's data without anyone needing to know the file formats, and patches that players apply to their own disc.

This file says what the project is for and how far each stage has got. TODO.md turns that into tasks, and DONE.md lists what is finished.

What a mod should be able to change

• The starting season. The state a new game begins in: schedules, competitions, league membership, clubs, squads and players. The game then plays on from there as normal.
• Data. Club, player, stadium and staff records, and the text that goes with them.
• Parameters. The tuning values in the TBB1/TBL1 tables and the executable: prices, growth rates, event odds, match settings and so on.
• Text. Message text in every language slot, including event dialogue, news and mail.

Graphics, models and sound are useful to extract, but editing them comes after the data above. The one exception planned is bringing Nexxus's LMAST Realism texture pack onto the disc (LMASTER_MOD.md).

The path there

Each stage builds on the one before it. The status below is a summary: TODO.md has the work left in each stage under the same numbers, and DONE.md what is finished.

0. Decrypt. Done. DATA.CVM's encrypted table of contents is decrypted with a key derived from its header, and DATA.ISO extracts to DAT/ (DATA_CVM_EXTRACTION.md).
1. Read. Document every file format and every folder in DATA.CVM in DOC/, and parse each format in SRC/, checked against every file on the disc. Nearly done: every folder has a doc, and the few files still unparsed are in the coverage table below.
2. Understand. Know what each field means in the game, not just its type and offset. A field can't be offered for editing until it has a name and a known range; fields still unknown stay read-only. Most of the work now: the player database, the starting season, the parameter tables, the economy and saves are named field by field. The match AI's files and each doc's "Still unknown" list are open.
3. Write. A writer for each format, which must round-trip: reading a file and writing it back gives the original bytes, checked over every file on the disc in regress.py. Done for what a starting-season mod changes, and edits through most writers are tested in PCSX2. The rest of the stadium tables and a texture writer are left.
4. Rebuild. Put edited files back on a disc image that boots. Done: patch_disc.py patches files of any size, moves them, grows the disc, updates every copy and rebuilds archives, all tested in PCSX2 (REBUILD.md).
5. Edit. GUI tools on top of the writers, organised by what a player of the game would recognise (a club, a player, a season) rather than by file, which check values against the documented ranges and cross-references. Mostly done: editor.py has a tab for every writer of game data except schedule.py's and sqb.py setcmd (they edit commands, not values), and builds a disc or a patch; saveedit.py edits a career save. A tab for each writer still to come (section 3 of TODO.md) is left.
6. Distribute. Share mods as xdelta patches (VCDIFF, RFC 3284) against the player's own unmodified disc image, never as game data or disc images, so no game data leaves the user's machine. Players apply them with tools they already have, such as Delta Patcher. Done: vcdiff.py makes and applies them (patches xdelta3 made too), the tools read CSO, ZSO and CHD images directly, a modded disc can keep its own saves, and INSTALL.md is the players' guide.

Alongside the stages, the LMASTER Mod is the project's own mod: fixes for what the release cut or broke, real names, a third tier and a harder economy, in three editions (lite, full and max). It is where most new findings get used first.

Coverage of DATA.CVM

The goal is that every folder in DAT/ has a doc saying what it holds and which scenes or systems load it, and every file type in it has a format doc and a tool whose info passes over all of DAT/. Nothing is left as "unknown binary". Even a format nobody plans to edit is documented, because an unexplained file can hide a dependency that breaks a rebuilt disc.

Where each folder stands (October 2026). The status is one of:

• done: every file type parses and is checked over all of DAT/. What is left is the meaning of some fields.
• most files: one or two file types aren't parsed yet.
• partly: several file types aren't parsed yet.

The "Still open" column is a summary. Each doc's "Still unknown" section has the full list, and TODO.md the tasks.

Folder	Holds	Status	Docs, tools	Still open
0SYSTEM/	UI colours, crest/badge/sponsor textures, fonts	done	0SYSTEM_DIR.md, system.py	what DETAILFLAG switches, which UI element uses each colour
ACROBATA/	875 Acroarts event scenes	most files	ACROBATA_DIR.md, acrobata.py	the ABDT scene layout, which code plays which scene
BG/	pre-rendered rooms' data, people, hands and props, trophies, the human database	done	BG_DIR.md, ZBF_FORMAT.md, NINJA_FORMAT.md, zbf.py, ninja.py, humanid.py	the room table's fields, what HUMANID.BIN's object kinds select, OR2 and IS
CSE/	2D screen layouts	done	CSE_FORMAT.md, csp.py	–
EMBLEM/	the club editor's crest and flag parts, the player editor's tables	most files, with a writer for the crest, flag and player-editor tables	EMBLEM_DIR.md, emblem.py	which choices pick some EDIT_PLAYER.TBB rows, what a part's rev values do
EVENT/	the event, news and mail tables	done	EVSDATABIN_FORMAT.md, EVENTDATA_TURN.md, evsdatabin.py	three NEWS columns, the condition and handler names
GAME/	match data: commentary, sound, models, tactics AI	partly	GAME_DIR.md, BPB_FORMAT.md, GAMEDATA_FORMAT.md, sounddat.py, ninja.py, bpb.py, gamedata.py, packdata.py	what the .CBB blocks and some combination areas select, which gait each play-book move order is, the rest of a GAMEDATA.BIN record, whether AI_PARAM.BIN is used, the cut-in pack's CIB0/BMT1 blocks, the RBD0 trailer, the SHADOWCOLLI/WALLCOLLI entries, TEAM.TMB
MESSAGE/	all message text	done, with a writer	MBB_FORMAT.md, mbb.py	which value the screen-set variables hold
NEWS/	newspaper pictures and ranking months	done	NEWS_DIR.md, news.py	where ads and cartoons go on the page
PARAM/	the starting season, player database, game tables	most files, with writers	PARAM_DIR.md and the docs it links; initteam.py, teaminit.py, pbdata.py, schedule.py, leaguesize.py, plrsim.py, plrcommon.py, regulation.py, clubresult.py, training.py, camp.py, formset.py, tour.py, clubrank.py, natcal.py	the values in PLRESOURCECOMMON.PAC entry 1 and table 4.1, a few schedule tables, what a few named player fields do
PLAYER/	faces, kits, player models	most files, with a kit writer	PLAYER_DIR.md, UNIFORM_FORMAT.md, packdata.py, uniform.py	the face block-4 header, a few kit fields
PRELOAD/	copies of other files for bulk loading	done, with a writer	PRELOAD_DIR.md, preload.py	–
SEQ/	the root sequencer scripts	most files	SEQ_DIR.md, SQB_FORMAT.md, sqb.py	two unused 2004 scripts, WPX
SOUND/	28 sound banks: effects and music	done	SOUND_DIR.md, sounddat.py	which screen plays which music, 4 banks the code never names
STADIUM/	stadium models, crowds, adverts	done, with a writer for the looks and boards	STADIUM_DIR.md, stadium.py	byte +0x0c of your stadium record, the crowd palettes
TEST3D/	the developers' test data	most files	TEST3D_DIR.md	SHADOWCOLLI.LBI, who reads 110 of the 163 files
CVS/ and */CVS/	the developers' version-control metadata, not read by the game	done	CVS_DIR.md, cvs.py	–

Outside DATA.CVM, the disc's AUDIO/ folder (music, commentary, chants and ambience) is done in AUDIO_DIR.md, the DLL/*.REL overlays in SNR2_FORMAT.md, and memory-card saves in SAVE_FORMAT.md. OPMOVIE.SFD (Sofdec video) is not studied.

Principles

• The docs come first. A value is edited through a tool only when its meaning is documented, labelled confirmed or empirical like every other claim in DOC/.
• Never corrupt a save or a disc silently. Writers validate their output by reading it back. The GUI refuses values that break a documented constraint and doesn't guess.
• Keep the tools usable without the GUI. Every edit a GUI can make is also a python SRC/... command, so changes can be scripted, diffed and reviewed. The editors log the command behind each save.
• Keep the setup light. The standard library only, as elsewhere in SRC/. tkinter ships with Python and fits that rule for the GUI.
• English first. The project serves the English-speaking LMAST community. The tools read the Japanese release too, but work on it comes later. It is still part of finishing (below), and LMASTER 1.0.0 needs every switch to work on it (Nexxus's choice, 2026-11-01).

When the reverse engineering is complete

Nexxus's definition (2026-11-01): the reverse engineering is complete when every file, every line of code and every mechanic of the game is fully documented, on both releases, and the mod editor and the save editor work on the Japanese release as on PAL. The stages above get the data editable well before that; this is the end point after them.

Only then might a follow-on project begin: LMAST-Recompiled, a full decompilation of the game, recompiled, ported to other platforms and expanded. It would be a project of its own, built on these docs.

Out of scope

• Distributing the game, its data, or patched disc images.
• Changes that need new game code, until the data side is done. Small patches are fine where they flip switches already in the code (the tutorial skip, the developer launcher, separate saves) or restore content the release cut or broke with the smallest change that works (the LMASTER Mod: the sponsor negotiation, the rival's manager, the camp list's loop bound). Each is a named patch_disc.py switch, tested in PCSX2. The one larger piece of new code is the third tier's, which had to grow the save to hold the extra clubs (LMASTER_MOD.md).
• Decompiling, recompiling or porting the game. That is LMAST-Recompiled's, a possible later project (above).