JUSDecomp 0.3.1

JUSDecomp 0.3.1

Quality-of-life and general performance release.

• Adds the F9 in-game settings menu with correctly oriented text.
• Adds F10 turbo toggle, F11 FPS/status overlay, and F12 screenshots.
• Reduces sampled scheduler host cost by about 29% in the measured gameplay run.
• Preloads and batch-registers cached native overlay banks before boot.
• Moves overlay maintenance out of the scheduler hot loop and reduces dispatch diagnostic overhead.
• Adds rolling gameplay frame-time percentiles, deadline misses, renderer state, overlay queues, and network queue/drop telemetry.
• Includes 334 pre-seeded native overlay DLLs for the Windows release.

The startup FMV remains excluded from gameplay FPS conclusions; the performance work targets normal menus and battles.

Validation: Linux and MinGW Release builds, all 14 runner tests, a 50-million-cycle smoke run, and bounded interactive gameplay soaks.

SHA-256 (JUSDecomp-0.3.1.zip):
0dda08d63e31dbd297ece2f5a1a0fc7e8098b469f23533761ecc101b2caeafa1

v0.3.0 — Linux support

v0.3.0 — Linux support

JUSDecomp now runs natively on Linux, with the same feature set as the
Windows app: the recompiled runner (SDL2 + OpenGL 4.3 compute renderer,
software-renderer fallback), a GTK launcher with full parity, online WiFi
Battle over Wiimmfi, and runtime mods.

Linux quick start (source build — see
docs/LINUX.md):

sudo pacman -S --needed cmake ninja gcc sdl2 gtk3 python git   # Arch/Omarchy
# or the equivalent SDL2 + GTK3 dev packages on your distro
tools/scripts/build_linux.sh
launcher/build-linux/JUSDecomp

The build verifies your ROM dump, compiles the runner and launcher, and
pre-compiles the native code cache (328 overlay banks) so the game boots
at full speed — no first-session convergence, no background compiler.

Framerate fix included: without the pre-seed, a fresh Linux install ran
the RAM overlays on the Tier-3 interpreter (~30 fps) and compiled native
banks in the background for minutes while playing. Verified result with the
pre-seed: 59.4 fps at boot, zero interpreted instructions, idle compiler.
If a Linux install ever runs at about half framerate, run
python3 tools/scripts/live_preseed.py and relaunch.

Windows players: nothing changes — download JUSDecomp-0.3.0.zip
below, extract, run JUSDecomp.exe, and select your legally dumped ROM.

Known issues: unchanged from v0.2.2 (intro-video FPS dips on slower
machines, deck-builder FPS dips, occasional online micro-stutters,
friend-code refresh on relaunch, minor visual glitches on some stages). On
Linux, the ARM7 Wi-Fi driver pages converge in-session during the first
minutes of online play.

v0.2.2 — intro crash hotfix

v0.2.2 — intro crash hotfix

Fixes a silent crash-to-desktop a few seconds into the video intro on some
integrated-GPU machines (e.g. AMD Ryzen APUs with Vega graphics on current
Adrenalin drivers).

What was happening: the auto-selected OpenGL 4.3 compute renderer hit a
driver error (GL_INVALID_VALUE 0x0501) on its frame readback during the
intro, and the runner shut the session down cleanly (no dialog, no crash
dialog — the "crash" was a deliberate exit).

The fix: a runtime compute failure now automatically demotes to the
faithful threaded software renderer and the game keeps playing. Only the
accelerated 3D path is skipped for the rest of the session. Players can also
force the software path from boot with the NDS_3D_RENDERER=soft
environment variable.

Unchanged known issues: FPS drops during the video intro on slower
machines, deck-builder FPS dips, occasional online micro-stutters, and the
friend-code refresh on relaunch.

Download JUSDecomp-0.2.2.zip, extract, run JUSDecomp.exe, and select
your legally dumped ROM.

JUSDecomp 0.2.1 — online FPS fix

JUSDecomp 0.2.1 — online FPS fix

Online WiFi Battle now runs at ~60 fps (was ~35). Root cause: the WFC/DWC network stack (ARM9 ov008/ov010 + ARM7 wifi driver) ran on the Tier-3 interpreter because the online launchers never enabled live-overlay promotion. Full write-up: decomp/docs/ONLINE_FPS.md.

What's new

• GUI launcher now enables live-overlay promotion in online mode, pointing at the bundle's pre-seeded app/live-cache.
• WFC profile persistence — friend codes survive relaunches (--firmware-state-path under the user dir).
• Online mode (Wiimmfi) is on by default — just type a player name.
• Pre-seeded release bundle — every ROM overlay page is pre-compiled to native (328 pages / 328 DLLs), so the game boots fully native with no in-session convergence wait.
• The .cmd/.sh online launchers also enable live-overlay promotion (per-instance caches for 2P).

Known issue

Occasional sub-second micro-stutters during online play remain (documented in decomp/docs/ONLINE_FPS.md).

Download

JUSDecomp-0.2.1.zip — extract anywhere, run JUSDecomp.exe, and select your own legally dumped Jump Ultimate Stars ROM (sha1-gated). No game data is included.

v0.2.0 — Online WiFi Battle (Wiimmfi)

v0.2.0 — Online WiFi Battle (Wiimmfi)

Jump! Ultimate Stars now plays online through the public Wiimmfi/Kaeru
service — world-wide and on the same network — with no ROM patching (the
runner redirects the game's DNS). Validated 2026-08-25: room created +
joined with distinct friend codes on one machine, and a successful
cross-network match (this PC ↔ a laptop on a 5G hotspot, no relay).

What's new

• Online WiFi Battle via Wiimmfi. The launcher's Settings now include
  Online mode (Wiimmfi) and a player name field.
• Peer-unicast WFC relay fix — relayed Wiimmfi NATNEG peer frames are
  delivered unicast-to-self, resolving the previous match-completion timeout
  (error 80430).
• New wiilink WFC provider (--wfc-provider wiilink, DNS
  167.235.229.36) for A/B testing against the default Kaeru route.
• Online test guide bundled in docs/ONLINE_TEST.txt (two-PC same-network and
  world-wide procedures).

Known issues

• FPS drops during online play — online battles run at roughly 35 fps
  instead of the offline 60 fps (observed on both machines); being
  investigated.
• Friend code refreshes on relaunch — closing and reopening the app
  regenerates the friend code; going online then shows a UID-mismatch warning
  and prompts an update (which lets you play again, but friends must be
  re-added). Being investigated.
• Intro-video and deck-builder fps drops, and minor stage rendering glitches
  (see the README).

Files

• JUSDecomp-v0.2.0.zip — the self-contained bundle: launcher + game engine
  (recompiled runner) + English Translation mod. You supply your own legally
  dumped Jump Ultimate Stars ROM.

JUSDecomp v0.1.1 - hotfix (0xc000007b launch crash)

JUSDecomp v0.1.1 — hotfix

Fixes the 0xc000007b (STATUS_INVALID_IMAGE_FORMAT) startup crash reported on
clean machines when launching the public release's JUSDecomp.exe.

What was wrong

The release packager only bundled the launcher's runtime DLLs (SDL2.dll,
libwinpthread-1.dll) inside app/ for the runner, not next to
JUSDecomp.exe at the bundle root. Windows never searches the app/
subdirectory, so on machines without MSYS2 on PATH the 64-bit launcher
resolved a wrong-architecture SDL2.dll from System32/PATH → 0xc000007b.
It only worked on the build machine because MSYS2's ucrt64\bin was
reachable there.

Fix

• Release packaging now ships SDL2.dll (and the MinGW runtime DLLs) next to
  JUSDecomp.exe at the bundle root.
• The launcher now statically links libstdc++ and libwinpthread, so its
  only non-system runtime dependency is SDL2.dll — which ships alongside it.
• Launcher version bumped to 0.1.1.

Install

Extract the .rar and run JUSDecomp.exe. It is fully portable (settings and
saves are stored next to the executable). You must provide your own legally
dumped Jump Ultimate Stars (Japan) ROM. No MSYS2 or runtime installation is
required.

Asset

• JUSDecomp-v0.1.1-portable.rar (11.76 MB)
  • SHA-256: 9C153C938E69B25C2AD425CE0C7D2D1DB864E8A6E9C42031B8C70A801545E92D

Version 0.1

JUSDecomp v0.1.0 — first public release

Jump Ultimate Stars, running natively on Windows — no emulator, no ROM included. Bring your own legally dumped copy of the game (sha1-gated to the stock dump).

What's in this release

• Native recompilation of the full game via ndsrecomp: dual-CPU scheduler, recompiled ARM9/ARM7 banks, overlay promotion, melonDS-derived 3D/Wi-Fi, SDL host. Full intro, in-game saves, deck injection, and arcade-stick input.
• Beginner-friendly launcher — pick your ROM in a file dialog (verified automatically), one-click Play, in-app settings, save import/delete, session logs.
• English Translation mod (bundled, on by default) — a faithful reproduction of the community English patch, layered over your Japanese ROM at runtime. The stock ROM is never modified.
• Keyboard remapping — Settings → Map keyboard... to rebind any of the 12 DS buttons (defaults: Z/X = A/B, A/S = Y/X, Q/W = L/R, arrows, Backspace/Enter = Select/Start).
• Controller setup — guided button capture for gamepads, saved between sessions.

How to play

1. Download JUSDecomp-v0.1.0.zip and extract it anywhere.
2. Run JUSDecomp.exe.
3. Click Change ROM... and select your own Jump Ultimate Stars.nds (unmodified dump).
4. Click Play Jump Ultimate Stars.

Known issues (v0.1.0)

• FPS drops during the video intro (gameplay after the intro runs at full speed).
• FPS drops on the deck builder.
• Minor visual glitches on some stages (scrolling background elements).

Legal

This project contains only original code and documentation. No Nintendo/Bandai/Shueisha assets are distributed — you must supply your own legally dumped copy of the game. This is an independent, educational work, not affiliated with or endorsed by Nintendo, Bandai Namco, or Shueisha. Licensed under the MIT License.