rgterm

A minimalist terminal emulator for muOS on Anbernic handheld devices, built from scratch in C with SDL2.

Completely vibe coded using Claude Opus 4.6 by Anthropic and Gemini 3.1 Pro by Google — zero prior SDL2 or PTY experience required.

Features

• Full VT100/ANSI escape sequence parser (colors, cursor movement, erase operations)
• 256-color and truecolor (24-bit) support
• On-screen keyboard (OSK) with 3 layers: abc, ABC, Ctrl
• Scrollback buffer (500 lines, configurable)
• Adaptive FPS (30 active / 5 idle) for battery efficiency
• Blinking cursor with left/right navigation in shell input
• muOS yellow color theme
• Configurable via res/rgterm.ini
• Runs /bin/bash with full PTY support

Tested on

Anbernic RG35XXSP running muOS 2601.1 Funky Jacaranda

May work on other muOS-supported devices, but is untested.

Controls

Button	Action
X	Toggle OSK (on-screen keyboard)
Select	Enter / confirm command
B	Backspace
L1 / R1	Switch OSK layer: abc → ABC → Ctrl
D-pad (OSK visible)	Navigate OSK keys
D-pad UP/DOWN (OSK hidden)	Scroll history
D-pad LEFT/RIGHT (OSK hidden)	Move cursor in input line
Start	Exit rgterm

OSK Layers

Layer	Contents
abc	Lowercase QWERTY + numbers + symbols
ABC	Uppercase QWERTY + F1–F12 + Home/End/PgUp/PgDn
Ctrl	Ctrl shortcuts (C-a through C-z, C-[, C-], etc.)

Installation

From release (recommended)

1. Download rgterm.muxzip from the Releases page
2. Copy it to /mnt/mmc/ARCHIVE/ on your device
3. Open Applications → Archive Manager and install it
4. Launch from Applications → rgterm

Manual installation

# Copy files to your device via SCP
scp -r rgterm res/font.ttf res/rgterm.ini mux_launch.sh \
    root@<device-ip>:/mnt/mmc/MUOS/application/rgterm/

Make sure the binary is executable:

chmod +x /mnt/mmc/MUOS/application/rgterm/rgterm
chmod +x /mnt/mmc/MUOS/application/rgterm/mux_launch.sh

Configuration

On first launch, res/rgterm.ini is created automatically with default values:

# rgterm configuration
font_path = res/font.ttf
font_size = 14
scrollback_lines = 500
fps_active = 30
fps_idle = 5
idle_timeout_ms = 500
fg_color = 255,200,0
bg_color = 0,0,0
shell = /bin/bash

Building from source

Requirements

• gcc-aarch64-linux-gnu
• SDL2 (aarch64)
• SDL2_ttf (aarch64)
• A monospace font at res/font.ttf (e.g. JetBrains Mono)

Quick build

# Install cross-compiler
sudo apt install gcc-aarch64-linux-gnu cmake make git

# Clone and build SDL2 + SDL2_ttf for aarch64
# (see BUILD.md for detailed instructions)

# Build rgterm
make clean && make

# Deploy to device
scp rgterm root@<device-ip>:/mnt/mmc/MUOS/application/rgterm/rgterm

See BUILD.md for full cross-compilation instructions.

Tips

• Use /opt/muos/bin/fastfetch for system info (the fastfetch command alone may not be in PATH)
• C-l clears the screen (Ctrl layer in OSK)
• C-c interrupts a running command (Ctrl layer in OSK)
• The scrollback buffer stores the last 500 lines — scroll up with D-pad when OSK is hidden

Limitations

• Screen is 640×480 — some TUI applications (like htop) may not render perfectly
• No mouse support
• No alternate screen buffer (yet)

License

MIT — see LICENSE

Credits

Built for muOS — Custom Firmware for Anbernic handheld devices.