Files
gen1recomp/docs/linux-arm-sbc.md
T
Shane McGovern 93e071bcaa Fix self-update on the PortMaster SBC build
The SBC and RG34XXSP ports hand LÖVE a source *directory*
(`love <dir>`), so `love.filesystem.isFused()` is false there and
`Boot.run` bailed on its first line.  The launcher still offered
"Update vX.Y.Z" and "Restart to update", so an update downloaded,
verified, and then was silently ignored forever.

- Boot.canUpdateInPlace() replaces the fused-only gate: a packaged
  build updates whether it is fused (AppImage, Flatpak game.love) or
  unpacked, and only a dev / source checkout (engine "0.0.0-dev") is
  excluded.  Fails closed when the host cannot be established.
  Prelaunch.updateAllowed now delegates to it, so the boot gate and the
  `--update` gate cannot disagree.
- Check.hostPort() reads the release-target marker, with
  POKEPORT_HANDHELD as a legacy fallback (the SBC launcher has always
  exported it, so packs predating this change still identify
  themselves).  The marker was read from the environment but never
  exported, so a full-package fallback on a handheld resolved to a
  desktop AppImage that cannot run there.
- A handheld now fetches its own package ("Download port update",
  reusing the worker's cross-platform download_full) instead of
  offering a URL it has no browser to open, and reports "Update package
  ready" once it is in the save directory for a manual re-extract.
- Launchers export POKEPORT_PORTMASTER / POKEPORT_RG34XXSP.

An in-place update only ever mounts a payload over the running source,
so relaxing the gate is less invasive than the fused path it joins.
A runtime bump still needs a full package, which the minShell gate
already reports as needs_full.

Tests: tests/engine/update_boot_host_gate.lua (new, 10 checks) pins the
gate; update_check_tests.lua pins both port asset names and hostPort().
scripts/test.sh --quick: all tiers passed; scripts/lint.sh: 0 errors.

Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>
2026-09-19 22:15:02 +01:00

5.3 KiB

Linux ARM SBC Handhelds (PortMaster)

Download gen1recomp-*-sbc-portmaster.zip from the Gen1Recomp releases. This build targets 64-bit Linux ARM handhelds with PortMaster, including compatible H700 devices.

Install

  1. Unzip the release. It contains gen1recomp-sbc.sh and a gen1recomp-sbc/ folder.
  2. Copy both as siblings into your device's PortMaster ports directory, commonly Roms/Ports (PORTS)/ or Roms/PORTS/.
  3. Install PortMaster for your firmware and refresh the Ports list.
  4. Copy your legally owned canonical US Red or Blue .gb file into gen1recomp-sbc/lovegame/.
  5. Launch gen1recomp-sbc from Ports and choose the ROM.

The pack includes portable.txt, so saves and ROM-derived cache remain beside the game on the SD card. The build never ships ROM-derived bytes.

Canonical US cart SHA-1 values:

  • Red: ea9bcae617fdf159b045185467ae58b2e4a48b9a
  • Blue: d7037c83e1ae5b39bde3c30787637ba1d4c48ce2

Updating

The port updates itself from the launcher. When a newer release exists the footer chip reads Update vX.Y.Z: press it to download the new version, then press Restart to update to relaunch and start using it. Nothing inside the port folder is rewritten, so an update that fails or is interrupted still boots the version you already had.

An update replaces the game's code and data. It cannot replace the LÖVE runtime the port ships, so a release that needs a newer runtime is applied differently: the chip then reads Download port update and saves gen1recomp-<version>-sbc-portmaster.zip into

gen1recomp-sbc/conf/love/pokemon-love2d/updates/

That case is finished on a computer — unzip the file and copy the gen1recomp-sbc.sh and gen1recomp-sbc/ it contains over the copies on the SD card, exactly as in Install above. Your saves sit beside the game (portable.txt) and are untouched by either kind of update.

The launcher exports POKEPORT_PORTMASTER=1, which is how the updater knows this is the PortMaster port and offers the port package rather than a desktop AppImage.

Controls

Input Action
D-pad Move cursor
A Click / confirm
L1 / R1 Switch tabs
Start / Select Play or choose ROM

In-game controls use the normal PortMaster/SDL mapping and can be rebound in OPTIONS → CONTROLS.

Runtime and suspend

The package bundles PortMaster's LÖVE 11.5 aarch64 runtime. The launcher sources control.txt, calls get_controls, applies an optional CFW override, invokes pm_platform_helper, and calls pm_finish on exit. Paths are relative to the launcher, allowing different firmware mount points.

Suspend/resume uses the existing LÖVE focus/visibility lifecycle: input is reset on focus loss and the game resumes when the window becomes visible again. Exact power-button behavior remains firmware-dependent; hardware validation has been performed on the TrimUI Brick, not every SBC or H700 device.

Power and Performance Tuning

The handheld build applies several optimizations to reduce power draw while keeping smooth frame pacing on low-power ARM SoCs:

  • PresentSync / driver vsync: Handheld builds keep driver vsync enabled so the unified present-sync stack can probe cadence and pace through the panel (KMSDRM page-flip wait). Disabling vsync here bypassed that path and forced the FrameCap 1 ms polling loop at 60 FPS.
  • Idle Render Governor: After POKEPORT_IDLE_AFTER seconds without input on static in-game screens, presentation drops to POKEPORT_IDLE_FPS while game logic and audio stay at full speed. Any button press restores full framerate on the next frame.
  • Sample Rate Scaling: Audio synthesis is tuned to 22.05 kHz by default (POKEPORT_AUDIO_RATE=22050), halving synthesis CPU overhead on Cortex-A53 cores with no audible quality loss on handheld speakers. The synth engine and its queueable source are built for one rate, so changing PERFORMANCE across the LOW boundary in OPTIONS switches the rate live and replays the current song from the start of its section; the rate never changes on its own during play.
  • Dynamic CPU Governor: Defaults to schedutil instead of pinning performance on all cores, reducing thermals and extending battery life.

Environment variables for fine-tuning (configured in gen1recomp-sbc.sh):

Variable Default Description
POKEPORT_IDLE_AFTER 10 Seconds without input before an idle screen drops presentation rate
POKEPORT_IDLE_FPS 6 Framerate while idle
POKEPORT_AUDIO_RATE 22050 Chip-synth sample rate (set to 44100 for full rate)
POKEPORT_CPU_GOVERNOR schedutil CPU scaling governor (schedutil, performance, ondemand)

Building

Release workflows build this automatically. Standalone builds resolve the latest published Gen1Recomp release by default:

./build-linux-arm-sbc.sh --version 0.1.75

For development, package a local checkout explicitly:

GEN1RECOMP_SOURCE_DIR="$PWD" ./build-linux-arm-sbc.sh --version 0.1.0
# or: ./build-linux-arm-sbc.sh --source "$PWD" --version 0.1.0

The generated port.json records the source release tag. install-linux-arm-sbc.sh is a macOS helper for copying a built pack to a mounted SD card.

PortMaster device support and runtime integration are maintained in the PortMaster ecosystem.