Pokémon Legends: Arceus

Update 1.1.1 (v262144) over the base game, SDK 11.4.0. Game Freak's engine between Pokémon Sword's (0100ABF008968000) and the Trinity engine of Pokémon Scarlet and Legends: Z-A, on NVN, with Havok physics, Wwise sound and Pia / NPLN networking. Modules main, subsdk0 (the movie module, which the profile does not load: main takes nothing from it the host does not supply), subsdk1 (GLSLC) and sdk; the sdk build (b39add63…) is Kirby and the Forgotten Land's (01004D300C5AE000). Started from the provisional profile the NSP script wrote from its survey (dm/games/profile_guess.py). Plays on the Mac at 30 fps, as on the Switch, from the first boot to free movement on the Obsidian Fieldlands beach (a short check, below). An unsigned IPA is built (4.2 GB); iOS is untested.

What it needs

No patches.py, and no host code keyed to this game.

Bring-up

• Resolved: a Break in nninitStartup (Break#1 reason=0 at sdk+0x39fb54, from StandardAllocator::Initialize at sdk+0x2f98e4 ← main+0x2779d8c). The host's cap lowered the allocator's 32 GB to 4.06 GB, but this sdk build aligns a region of 1 GB or more to 1 GB, so the region would have started at alias +1 GB and ended past the 4.38 GB alias region. The SDK-wide node-area patch matched this build (implementation 3), the alignment patch had no implementation for SDK 11.4: its placement helper (sdk+0x34e1d8) is the SDK 12.3.9 one with 8 more bytes. It is now the alignment patch's second implementation, and both cuts are registered for this build: a build a profile was brought up on takes only registered cuts, so with this profile in dm/games the SDK-wide rules no longer reached it (the Break came back once). The region lands at alias +0.06 GB.
• Resolved: an abort on Metal's compiler queue a few seconds into the language screen ([AGX] Failed assertion "error == MTLCompilerErrorNoError" in findOrCreateComputeFastClearPipeline, MTLCompilerService crash reports in AGCLLVMStatelessFragmentObject::buildBlendFactor), with or without the pipeline prebuild. The pipeline was ha_post_effects.bnsh variation 4 (f4f36a03b0c6691d): an RGBA16Float target blended with destination factor SRC1_ALPHA, the shader writing outputs 0 and 1. A temporary log of each blended attachment in pso_desc named it as the last pipeline before the abort. DM_NVN_DUAL_WANT then listed a second one, ff45da02e225f961, in the first minute.
• [RED] no render target could get an MTLTexture once at boot (Passes with no render target); no other red line on the route below.
• The NSP script's rewrite step was reused after the alignment rule was added: it keyed only the patch files that name one of the modules' builds (The packing script in detail).

Performance and memory

• On the Mac (M6): 30 fps as on the Switch (power lines: 30.0 fps, CPU 0.64 W, about 20% of a core), with long frames of 100–260 ms where new pipelines are first built (that run's archive was made for the near=−w depth mode, before depth_mode zero; the Mac build from this profile makes the near=0 bases, not measured on the route since). Resident memory 2.7 GB and 1.46 GB of Metal allocations on the beach after 7.5 minutes.

Files and shaders

• RomFS 6.0 GB, 19,101 files: effects (bin/effect, 2.5 GB), 678 GFPAK archives under bin/archive (1.6 GB, every entry Oodle Kraken: Oodle entries of GFPAK archives), Wwise banks (bin/sound/NX64/wwise/bank/Default.pck is the romfs_marker), message tables, compiled scripts (bin/haxe, .blua), and Trinity-style model files (.trmdl, .trmsh, .trmtr). The game probes arc/data.trpfd and arc/data.trfmd (Trinity's pack index), which it does not ship.
• Shaders: 12,851, by where each first appears: 11,352 in the effects' particle files (.ptcl), 1,386 in the loose BNSH files of system_resource/gfx2/shader (materials, terrain, water, grass, lighting, shadows, post effects), 73 in the GFPAKs, 40 in main. 6,156 pixel shaders, 5,474 of them write exactly colours 0 and 1.

Mac routes

• The work folder's run/boot.sh <log> [secs] VAR=value… runs build/plahost (a renamed copy of the host) on the NSP script's build, RomFS image and shader libraries; run/ctl.sh and run/step.sh <shot> [wait] <presses…> are Sword's (presses through DM_CTL, screenshots of the next frame). Run headless.
• From a fresh save (DM_KBD=<name> answers the name): A at the language screen (about 70 s after start with the archive opening and the first shaders), A presses through Arceus's questions and the name, the fall through the rift, waking on the beach, Professor Laventon and the three Pokémon, then the player walks (LUp, LRight).
• The route checked on the Mac: language, name, the opening, the beach with Laventon, Cyndaquil, Rowlet and Oshawott, and a walk through the grass toward the first marker. The game had not saved yet, so there is no reference save.

Found on this game

General changes first needed here; each applies to every game:

• The node area and 32 MB region alignment cuts of sdk b39add63…, and the SDK 11.4.0 implementation of the SDK-wide alignment patch (sdk_patches.py MATCH_CUTS; the build's row was removed on 2026-10-29, as the rules give the same cuts): 1 GB alignment of regions of 1 GB and more.
• Dual-source blending for NVN shaders (dmsh_build.py fs_dual, main0_d, the profile's dual_want.tsv, DM_NVN_DUAL_WANT; pso_desc pso_reads_src1): A written secondary blend source (NVN dual-source blending).
• The NSP script's rewrite key always covers sdk_patches.py (patch_files): The packing script in detail.