Vaka OS
Warning
Vaka OS is an early-stage experimental firmware project.
It is currently beta / experimental software and may be unsafe to run on real hardware.
Installing experimental firmware can brick your device, break OTA, or require SWD recovery.
Proceed only if you understand the risks.
Vaka OS is a Rust-first firmware project primarily targeting the PineTime smartwatch.
The project focuses on experimenting with a modern Rust embedded stack and a shared UI system that can run both on device and in a desktop simulator.
The primary goals are:
- Full Rust control over the firmware stack
- A simulator-driven development workflow
- A UI architecture reusable between firmware and simulator
- Safe OTA experimentation using a dual-firmware verification model
Workspace Layout
crates/
firmware/
simulator/
ui/
docs/
Readme.md
Cargo.toml
crates
- firmware – firmware running on the watch
- simulator – desktop environment for development
- ui – shared UI code usable by firmware and simulator
See docs/architecture.md.
docs
Supporting documentation.
Development Modes
Vaka OS supports two workflows.
Simulator / Development Mode
Used for fast iteration without flashing the device.
Typical loop:
edit code run simulator test behavior repeat
Used for:
- UI layout
- interaction logic
- application experimentation
Simulator success does not guarantee hardware success.
Device Mode (Build and Upload)
Used when testing on the actual PineTime hardware.
Typical loop:
- build firmware
- package OTA update
- upload to watch
- boot firmware
- verify behavior
See docs/development.md.
Dual Firmware Verification Model
PineTime firmware updates typically follow a dual-slot update model.
The device contains two firmware areas:
- slot A → currently running firmware
- slot B → new firmware update
Typical OTA update process:
- New firmware is uploaded to the inactive slot
- Bootloader boots the new firmware once
- Firmware runs in unconfirmed state
- User manually verifies functionality
- Firmware confirms itself
- Bootloader marks it as the new permanent firmware
If firmware fails to confirm:
reboot → bootloader restores previous firmware
This provides protection against broken updates.
Vaka OS intends to use a workflow compatible with this behavior.
OTA Safety Rules
Important development rules:
- Never overwrite the bootloader
- Always test new firmware as unconfirmed
- Keep a working firmware available
- Do not assume simulator success equals hardware safety
Documentation
See:
- docs/architecture.md
- docs/development.md
- docs/hardware.md
- docs/roadmap.md
Project Status
Early project setup and architecture exploration.