Game state

The games' own state: saves, scripted state, and behaviour that looks like a host bug but is not. Each entry: symptom, cause, fix, the games it was found on. The symptom index lists every symptom.

Game behaviour that is not a host bug

Most draws are in command buffers replayed later

• Symptom: "stuck" at a screen with one draw per frame.
• Cause: usually not stuck: most draws are in recorded command buffers replayed later.
• Fix: dump the passes (DM_NVN_PASSDUMP, 04, Diagnostic switches) before assuming the game logic is blocked.

Buttons mapped by position: B confirms

• Symptom: menus ignore A.
• Cause: not a host fault: the game maps its buttons by position, B confirms and A goes back (its prompts say so).
• Found on: DARK SOULS: REMASTERED (SDK 4.5.0). The first boot shows two notices before the title menu ("Unable to connect to the network", then "Game will start in offline mode"), and a new game first walks through Brightness, Options and Button settings.

Any Lua error quits a LÖVE game

• Symptom: a crash in main+0x339c00 a second or two into the title, in love-nx's video module teardown (love::video::theora::Video → ~Worker; its thread released the worker that the closing module deletes too).
• Cause: the Lua state was closing: on the Switch, Balatro's love.errhand returns at once, so any Lua error quits. A print at the top of love.errhand in a copy of the RomFS (DM_ROMFS=<copy>) gave the error: Shader uniform 'distortion_fac' does not exist (the capture run had no shader library, so every program linked with no uniforms), then bad argument #2 to 'send' (number expected, got boolean) (a bool uniform reported as GL_UNSIGNED_INT).
• Fix: look for the Lua error first; the two errors here were host faults in the GL layer's shaders and uniforms (see GL shaders put together at run time and captured and GL uniforms, pipelines and attributes).
• Found on: Balatro (SDK 18.3.2, LÖVE 11.4; one boot).
• Check: probing the destructors (DM_PROBE) and logging every object the Lua GC released (DM_PROBE=main:0x18b920@x0+0: the module proxies all at once) showed it was a shutdown, not a premature collection.

TV latency calibration's late, beat-timed listening window

• Symptom: the TV latency calibration ("press A when you hear the fourth beat") ignores A.
• Cause (not a host bug): docked, the first boot runs it (scene script main+0x4c0820). It starts listening only 0x3c0 frames (16 s) after the prompt, through the active controller (main+0x22b0 id 0x3ed, virtual button 4 = A), and passes when about ten presses keep a steady offset within −5 to +13 frames of the cue (evaluation main+0x2948c0; offset = cue ticks at +0x34 / about 17 ticks per frame, about 480 per beat).
• Testing it: scripted presses at fixed seconds drift off the beat; use frame-timed DM_KEYS at the bar period (117.12 frames at its 123 BPM) and read each press's offset with DM_PROBE=main:2951f0@34. A passed calibration is saved per TV panel identity (the host's all-zero one included, Default display panel identifier) and not asked again.
• Profile: it plays handheld with Boost (op_mode handheld, perf_mode boost), which skips the TV setup and keeps the 1080p draw size.
• Found on: Rhythm Heaven Groove (SDK 21.4.0).

Scripted state

The software keyboard in scripted runs (DM_KBD)

• Symptom: in a scripted run, a screen goes back by itself right after a confirm; the log shows swkbd: … → no window, treated as cancel.
• Cause: the confirm opened the system keyboard (swkbd, name entry). Without a window the host answers "cancel" by design.
• Fix: pass DM_KBD=<text> to answer it.
• Found on: Fire Emblem Engage (its appearance choice).

Player join screens (hid::StartLrAssignmentMode)

• Symptom: a player join screen that ignores A (a character select with four "L + R to join" slots after the title).
• Cause: the game calls hid::StartLrAssignmentMode and waits for L and R pressed together on the join screen itself, then a character choice with A.
• Fix: in DM_KEYS that is L+R~0.5 while the screen is up (presses on the title before it are lost).
• Found on: Super Mario 3D World + Bowser's Fury.
• Note: on the game select, holding the stick right for a second (7:LRight~1) switches to Bowser's Fury, which also uses nvnTextureGetSwizzle and nvnTextureGetStorageClass. Map and level movement read the left stick only: DM_KEYS takes LLeft / LUp / LRight / LDown. A working route into World 1-1 on a fresh save: DM_KEYS=6:A,10:A,14:L+R~0.5,17:A*3/2,24:Plus*6/3,45:A*6/3,66:LUp~1,70:A,74:LRight~1,78:A,82:LLeft~1,86:A (World 1-1 by frame ~6000).