Arch R

Arch Linux-based gaming distribution for R36S and all clones.

Leve como uma pluma.

Arch R is a custom Linux distribution built from scratch for the R36S handheld gaming console (RK3326 SoC, Mali-G31 GPU, 640x480 MIPI DSI display). It supports all R36S variants and clones with 18 different display panels.

Features

• Kernel 6.6.89 (Rockchip BSP) — custom DTS with joypad, panel init sequences, audio, USB OTG
• Mesa 26 Panfrost — open-source GPU driver, GLES 1.0/2.0/3.1, no proprietary blobs
• EmulationStation (fcamod fork) — 78fps stable, GLES 1.0 native rendering
• RetroArch 1.22.2 — KMS/DRM + EGL, 18+ cores pre-installed
• 19-second boot — U-Boot logo → kernel → systemd → EmulationStation
• Full audio — ALSA, speaker + headphone auto-switch, volume hotkeys
• Battery monitoring — LED warning, capacity/voltage/temp reporting
• Multi-panel support — 18 panel DTBOs (6 original R36S + 12 clones)

Quick Start — Flash a Pre-built Image

Download the latest image from Releases, then:

xz -d ArchR-R36S-*.img.xz
sudo dd if=ArchR-R36S-*.img of=/dev/sdX bs=4M status=progress
sync

Insert the SD card into your R36S and power on. First boot creates a ROMS partition automatically.

Building from Source

Host Requirements

• OS: Ubuntu 22.04+ (or any Linux with QEMU user-static support)
• Disk: 30GB+ free space
• RAM: 4GB+ recommended
• Time: ~3-4 hours (first build), ~1 hour (incremental)

Install Dependencies

sudo apt install -y \
    gcc-aarch64-linux-gnu \
    qemu-user-static \
    binfmt-support \
    parted \
    dosfstools \
    e2fsprogs \
    rsync \
    xz-utils \
    imagemagick \
    device-tree-compiler \
    git \
    bc \
    flex \
    bison \
    libssl-dev

Build Everything

git clone --recurse-submodules https://github.com/user/Arch-R.git
cd Arch-R

# Full build (kernel + rootfs + mesa + ES + retroarch + panels + image)
sudo ./build-all.sh

The flashable image will be at output/images/ArchR-R36S-YYYYMMDD.img.xz (~860MB compressed).

Build Individual Components

sudo ./build-all.sh --kernel     # Kernel only (~10 min)
sudo ./build-all.sh --rootfs     # Rootfs + Mesa + ES + RetroArch (~3 hours)
sudo ./build-all.sh --image      # Image assembly only (~2 min)
sudo ./build-all.sh --clean      # Remove all build artifacts

Build Pipeline

build-all.sh
  ├── build-kernel.sh          # Cross-compile kernel 6.6.89 (~10 min)
  ├── build-rootfs.sh          # Arch Linux ARM rootfs in QEMU chroot (~45 min)
  ├── build-mesa.sh            # Mesa 26 with Panfrost + GLES 1.0 (~30 min)
  ├── build-emulationstation.sh # ES-fcamod with 21 patches (~20 min)
  ├── build-retroarch.sh       # RetroArch + cores (~40 min)
  ├── generate-panel-dtbos.sh  # 18 panel DTBO overlays (~10 sec)
  └── build-image.sh           # Assemble SD card image (~2 min)

All builds happen inside a QEMU aarch64 chroot — no cross-compilation issues.

Project Structure

Arch-R/
├── build-all.sh                  # Master build orchestrator
├── build-kernel.sh               # Kernel compilation
├── build-rootfs.sh               # Root filesystem (Arch Linux ARM + services)
├── build-mesa.sh                 # Mesa 26 GPU driver
├── build-emulationstation.sh     # EmulationStation frontend
├── build-retroarch.sh            # RetroArch + cores
├── build-image.sh                # SD card image assembly
├── config/
│   ├── archr-6.6-r36s.config     # Kernel config fragment (393 options)
│   ├── boot.ini                  # U-Boot fallback boot script
│   ├── es_systems.cfg            # EmulationStation system definitions
│   ├── retroarch.cfg             # RetroArch base configuration
│   ├── asound.conf               # ALSA audio configuration
│   └── autoconfig/               # RetroArch controller autoconfig
├── kernel/
│   └── dts/
│       ├── rk3326-gameconsole-r36s.dts  # Custom R36S device tree
│       └── R36S-DTB/                     # Reference panel DTBs
├── scripts/
│   ├── emulationstation.sh       # ES launch wrapper
│   ├── retroarch-launch.sh       # RetroArch launch wrapper
│   ├── archr-hotkeys.py          # Volume/brightness hotkey daemon
│   ├── first-boot.sh             # First boot setup (ROMS partition)
│   ├── generate-panel-dtbos.sh   # Panel overlay generator
│   ├── pmic-poweroff             # PMIC shutdown handler
│   └── vlc-stub.c                # VLC stub library for ES build
├── bootloader/
│   └── u-boot-r36s-working/      # Pre-built U-Boot binaries
├── prebuilt/
│   └── cores/                    # Pre-built RetroArch cores (FBNeo, MAME, N64, PSP)
├── ArchR.png                     # Boot logo source
└── ROADMAP.md                    # Development diary

Hardware

Component	Details
SoC	Rockchip RK3326 (4x Cortex-A35 @ 1.5GHz)
GPU	Mali-G31 Bifrost (Mesa Panfrost, 600MHz)
RAM	1GB DDR3L (786MHz)
Display	640x480 MIPI DSI (18 panel variants)
Audio	RK817 codec, speaker + headphone jack
Storage	MicroSD (boot + rootfs + ROMS)
Controls	D-pad, ABXY, L1/L2/R1/R2, dual analog sticks
Battery	3200mAh Li-Po (RK817 charger)
USB	OTG with host mode (VBUS power on GPIO0_B7)

Supported Panels

Arch R supports 18 display panels via DTBO overlays. The default image boots with Panel 4-V22 (the most common R36S panel).

Panel Auto-Detection

On first boot, Arch R runs a panel detection wizard that guides you through selecting your display panel:

1. If your screen works (you see text on screen): press A to confirm the current panel
2. If your screen is black (wrong panel): listen for audio beeps and use buttons to navigate:
   • Each panel plays a different number of beeps (1 beep = first panel, 2 beeps = second, etc.)
   • Press B to skip to the next panel
   • Press A to confirm (you'll hear 3 rapid beeps)
   • The system reboots with the correct panel applied

Your selection is saved permanently. To reset it later, hold X during boot.

Panel List

#	Panel	Notes
1	Panel 4-V22 (default)	Most common (~60% of R36S units)
2	Panel 3-V20	V20 board marking
3	Panel 5-V22 Q8	V22 Q8 variant
4	Clone Panel 8	ST7703 (G80CA-MB)
5	Panel 0	Early R36S units
6	Panel 1-V10	V10 board marking
7	Panel 2-V12	V12 board marking
8	Clone Panel 1	ST7703
9	Clone Panel 3	NV3051D
10	Clone Panel 7	JD9365DA
11	Clone Panel 9	NV3051D
12	Clone Panel 10	ST7703 variant
13	Clone Panel 2	ST7703
14	Clone Panel 4	NV3051D
15	Clone Panel 5	ST7703
16	Clone Panel 6	NV3051D
17	R36 Max	720x720 ST7703
18	RX6S	NV3051D variant

Manual Panel Selection

If you prefer to set the panel manually (e.g., you know which panel you have from ArkOS/dArkOS):

Step 1 — Mount the BOOT partition on your PC

lsblk
sudo mount /dev/sdX1 /mnt

Step 2 — Create panel.txt

# Example: Panel 3-V20
echo 'PanelNum=3
PanelDTBO=ScreenFiles/Panel 3/mipi-panel.dtbo' | sudo tee /mnt/panel.txt

# Mark as confirmed (skip wizard on next boot)
echo 'confirmed' | sudo tee /mnt/panel-confirmed

For default Panel 4-V22 (no overlay needed):

echo 'PanelNum=4
PanelDTBO=' | sudo tee /mnt/panel.txt
echo 'confirmed' | sudo tee /mnt/panel-confirmed

Step 3 — Unmount and boot

sudo umount /mnt
sync

To reset panel selection: hold X during boot, or delete panel-confirmed from the BOOT partition.

Boot Flow

Power On
  → U-Boot (idbloader → trust → uboot.img)
  → logo.bmp displayed on screen
  → boot.ini: load panel.txt → apply DTBO overlay (if non-default panel)
  → Kernel 6.6.89 + rk3326-gameconsole-r36s.dtb
  → systemd → panel-detect.service (first boot only)
  → archr-boot-setup (GPU + governors)
  → emulationstation.service → EmulationStation UI
  ≈ 19 seconds total (+ wizard on first boot)

Contributing

See ROADMAP.md for current development status and planned features.

License

GPL v3