RaspOVOS

June 18, 2025 · View on GitHub

Using dtcooper/rpi-image-modifier, we download a raspios_lite_arm64 image and modify it to install OVOS on top.

The customized images are then uploaded to GitHub Releases. 🎉

RaspOVOS

What raspOVOS Does to Raspberry Pi OS

Getting Started

Check out the Getting Started Guide for instructions.

Find the latest images on the Releases page.

⚠️ These builds are semi-automated and might not be well tested

Important Notes

Default user: ovos
Default password: ovos
Default hostname: raspOVOS
OVOS services run under the ovos user, with autologin enabled.

⚠️ DO NOT change the default user when burning the image or you will run into issues

Image Variants

lite images delegate STT and TTS to public servers and have a minimal intents pipeline
hybrid images delegate STT to public servers, run TTS on device and have a balanced intents pipeline
offline images run STT and TTS on device and have a full intents pipeline

⚠️ online servers are hosted by volunteers and provided on a best effort basis, latency and uptime might vary wildly per request

In general the following plugins are used for all images

image_type	stt-plugin	tts-plugin	m2v-intent-model
offline	ovos-stt-plugin-citrinet	ovos-tts-plugin-piper	ovos-model2vec-intents-LaBSE
hybrid	ovos-stt-plugin-server	ovos-tts-plugin-piper	ovos-model2vec-intents-LaBSE
online	ovos-stt-plugin-server	ovos-tts-plugin-server	N/A

System requirements

lite images might work in a rpi3
hybrid images recommend at least a rpi4
offline images need at least 4GB RAM, preferably 8GB

💡 Please consider self-hosting your own TTS and STT servers in a more powerful device

Language specific plugins and models

The following language specific plugin configurations are used

lang	tts-plugin
ca	ovos-tts-plugin-matxa-multispeaker-cat
gl	ovos-tts-plugin-nos
eu	ovos-tts-plugin-ahotts

lang	stt-plugin	stt-model
da	ovos-stt-plugin-fasterwhisper	Systran/faster-whisper-base
gl	ovos-stt-plugin-fasterwhisper	Jarbas/faster-whisper-base-gl-cv13
eu	ovos-stt-plugin-fasterwhisper	Jarbas/faster-whisper-base-eu-cv16
es	ovos-stt-plugin-citrinet	Jarbas/stt_es_citrinet_512_onnx
ca	ovos-stt-plugin-citrinet	neongeckocom/stt_ca_citrinet_512_gamma_0_25
pt	ovos-stt-plugin-citrinet	neongeckocom/stt_pt_citrinet_512_gamma_0_25
de	ovos-stt-plugin-citrinet	neongeckocom/stt_de_citrinet_512_gamma_0_25
it	ovos-stt-plugin-citrinet	neongeckocom/stt_it_citrinet_512_gamma_0_25
nl	ovos-stt-plugin-citrinet	neongeckocom/stt_nl_citrinet_512_gamma_0_25
en	ovos-stt-plugin-citrinet	neongeckocom/stt_en_citrinet_512_gamma_0_25
fr	ovos-stt-plugin-citrinet	neongeckocom/stt_fr_citrinet_512_gamma_0_25

lang	intent-model
mul	ovos-model2vec-intents-LaBSE
en	ovos-model2vec-intents-potion-32M
ca	ovos-model2vec-intents-roberta-large-ca-v2-massive
gl	ovos-model2vec-intents-bertinho-gl-base-cased
eu	ovos-model2vec-intents-BERnaT-base
pt	ovos-model2vec-intents-serafim-335m-portuguese-pt-sentence-encoder
es	ovos-model2vec-intents-roberta-large-bne

NOTE: intent models are still undergoing training for some languages and might not actually be shipped yet

What raspOVOS Does to Raspberry Pi OS

raspOVOS is a customization layer for Raspberry Pi OS that transforms a standard base image into a fully functional, voice-enabled smart assistant platform powered by OpenVoiceOS (OVOS). Here’s what the installation script modifies and installs:

System Configuration

User Customization:

Renames the default pi user to a custom user (default: ovos).
Updates all references in system files (/etc/passwd, /etc/group, /etc/shadow) and moves the home directory.
Sets a default password (ovos) and ensures it's reflected across boot and login settings.
Adds the user to critical groups: sudo, audio, pipewire, rtkit, and a custom ovos group.

Hostname:

Sets a custom hostname (raspOVOS).

Performance Tuning:

Modifies /etc/fstab via setup_fstab.sh to optimize disk usage and performance (e.g., zram swap).

System Dependencies

Installs essential system tools and packages, including:

Build and development tools: build-essential, swig, python3-dev, libssl-dev, etc.
Audio stack: pipewire, wireplumber, alsa-utils, portaudio, mpv, ffmpeg, etc.
Camera support: python3-libcamera, python3-kms++.
DLNA/Media support: gstreamer, libupnp, gmediarender.

File System Overlays

The file overlays introduce services, configs, and utilities specific to the OVOS runtime environment:

├── etc
│   ├── modules-load.d/i2c.conf                      # Ensures i2c modules are loaded on boot
│   ├── mycroft/mycroft.conf                         # Default OVOS config optimized for raspberry pi
│   ├── systemd/system/                              # Systemd service units
│   │   ├── i2csound.service                          # I2C audio board init
│   │   ├── ovos-admin-phal.service                   # Enables admin PHAL (root PHAL plugins)
│   │   ├── splashscreen.service                      # Boot splash screen
├── home
│└── ovos
│    ├── nltk_data                                    # Preloaded NLTK tokenizers, corpora, taggers
│    ├── .config
│    │└── mycroft
│    │    └── mycroft.conf                            # language specific configuration 
│    └── .local
│        └── share
│            ├── mycroft
│            │└── word_corrections.json               # ovos-utterance-corrections-plugin config to improve STT
│            └── vosk
│                └── vosk-model-small-xxx             # vosk model for wake word
├── opt/ovos/
│   ├── splashscreen.png                              # OVOS splash image
│   └── tag                                           
├── usr/libexec/                                      # system signals for ovos-bus:
│   ├── ovos-clock-sync                               
│   ├── ovos-i2csound                                 
│   ├── ovos-librespot                                
│   ├── ovos-ocp-*-signal                             
│   ├── ovos-reboot-signal                            
│   ├── ovos-shutdown-signal                          
│   ├── ovos-ssh-*-signal                             
│   ├── ovos-stop                                     
│   ├── ovos-systemd-* (admin, audio, gui, etc.)     # Systemd wrapper launchers for core subsystems
├── usr/local/bin/
│   ├── ovos-*                                         # CLI tools: ovos-update, ovos-help, ovos-reset-brain, etc.
│   └── ls-*                                           # List available STT, TTS, skills, wakewords, etc.

These overlays ensure:

OVOS boots as a system-managed, modular assistant.
OS-level actions like reboot, shutdown, clock sync, or SSH enable/disable emit OVOS bus messages.
Splashscreen and audio initialization integrate tightly with boot services.
Tools like ovos-update and ovos-reset-brain provide maintenance and troubleshooting from CLI.

Python Environment Setup

Installs uv and sdnotify globally.
Creates a Python virtual environment at ~/.venvs/ovos.
Installs core OVOS components and their dependencies inside the venv:
- ovos-core, ovos-gui, ovos-audio, ovos-phal, ovos-skill-config-tool, etc.
- STT/TTS plugins like ovos-stt-plugin-fasterwhisper, ovos-audio-transformer-plugin-ggwave.

Models and Skill Enhancements

Downloads and installs:
- model2vec multilingual intent classification model.
- fasterwhisper for fast, lightweight speech-to-text with language detection.
Sets up Hugging Face shared model cache under the ovos user for efficient reuse across plugins.

Raspberry Pi Optimizations

Here is an overview of non-OVOS specific changes to the base raspios-lite image

Change	Description	Benefit for Hardware Performance
Base raspiOS image runing	Reduces GPU memory, enables i2c/spi, enables autologin, change user name...	optimizes the base system to run OVOS
Install Pipewire	Installs PipeWire for sound server management, configures user permissions for audio groups, and sets up `.asoundrc` for default audio handling.	Provides a low-latency audio server for audio management, ensuring smooth and high-quality sound handling.
Install KDEConnect	Installs KDEConnect to enable integration with your phone	Easy file and clipboard sharing
Tune fstab	Updates `/etc/fstab` to include `noatime` and `nodiratime` options, reducing disk I/O by not updating access times on reads.	Reduces unnecessary disk operations, leading to faster system performance and reduced wear on SD cards.
Passwordless nmcli	Configures NetworkManager settings to disable Wi-Fi power-saving and grants the "network" group permission to change settings.	Ensures consistent network connectivity and performance, avoiding interruptions or delays that may affect latency.
Tune sysctl	Configures kernel tuning parameters for improved network and memory performance, optimizing system responsiveness for real-time tasks.	Improves network and memory performance: Faster network response, better memory management for smoother operation.
	- `net.ipv4.tcp_slow_start_after_idle=0`: Disables slow start for idle TCP connections.	Reduces latency when establishing new connections, enhancing real-time communication
	- `net.ipv4.tcp_tw_reuse=1`: Enables reuse of TIME_WAIT sockets.	Reduces time delays for connections by allowing reuse of sockets, benefiting long-running services
	- `net.core.netdev_max_backlog=50000`: Increases the maximum number of packets that can be queued for processing.	Improves network packet processing, reducing latency during high network activity.
	- `net.ipv4.tcp_max_syn_backlog=30000`: Increases the maximum backlog of pending TCP connections.	Ensures the system can handle more incoming TCP connections, improving network stability for real-time tasks.
	- `net.ipv4.tcp_max_tw_buckets=2000000`: Increases the maximum number of TCP connections in TIME_WAIT state.	Helps manage a higher number of concurrent connections, reducing connection delays in a busy network environment.
	- `net.core.rmem_max=16777216`, `net.core.wmem_max=16777216`: Increases maximum buffer sizes for receiving and sending data.	Optimizes network throughput by allocating more memory for buffer handling.
	- `net.core.rmem_default=16777216`, `net.core.wmem_default=16777216`: Sets default buffer sizes for receiving and sending data.	Ensures better performance in network communication, reducing potential lag.
	- `net.ipv4.tcp_rmem="4096 87380 16777216"`, `net.ipv4.tcp_wmem="4096 65536 16777216"`: Configures TCP buffer sizes for receiving and sending data.	Fine-tunes the memory allocation for TCP, enhancing network efficiency.
	- `net.core.optmem_max=40960`: Sets maximum size for socket options memory.	Reduces delays in setting socket options, improving responsiveness for real-time communication.
	- `fs.inotify.max_user_instances=8192`, `fs.inotify.max_user_watches=524288`: Increases the number of file system watches.	Optimizes system performance by allowing more file monitoring, which can benefit real-time data processing tasks.
udev rules	Configures udev rules for setting I/O scheduler for MMC and USB devices to "none", minimizing latency for disk and removable storage.	This can reduce latency and improve performance for flash-based storage like MMC and USB devices. Flash storage does not require complex scheduling algorithms because it has no moving parts (like hard drives), so a simpler, more direct I/O approach is more efficient.
Disable Wi-Fi power-saving	Copies the `wlan0-power.service` systemd service file to `/etc/systemd/system/` and enables it to manage Wi-Fi power consumption.	Reduces power consumption by disabling Wi-Fi power-saving features, which is important for maintaining stable network performance.
Setup ZRAM	Installs and configures ZRAM to create compressed swap space in RAM, improving system performance by reducing disk swap usage.	Enhances system performance by reducing reliance on slower disk-based swap and utilizing faster RAM for swap, which is especially useful on limited-resource devices like Raspberry Pi.
	`vm.swappiness=100`	Increases the system's tendency to use swap space (even if there is available RAM), which helps with memory management and reduces disk I/O.
	`vm.page-cluster=0`	Lowers the number of pages to swap at once, making memory swapping more granular and efficient in cases of memory pressure.
	`vm.vfs_cache_pressure=500`	Reduces pressure on the VFS cache, ensuring more data stays in memory for faster file access, which is important for real-time applications.
	`vm.dirty_background_ratio=1`	Reduces the amount of memory that can be used before data is written to disk, ensuring data is written more frequently and preventing memory overload.
	`vm.dirty_ratio=50`	Controls the threshold at which dirty pages (pages that need to be written to disk) trigger writes. A higher value means more data is kept in memory before writing to disk.