Reachy Mini Flasher

Cross-platform (Windows / macOS) desktop app to reflash the ReachyMiniOS image onto a Reachy Mini Wireless, over USB only.

It rewrites the full OS image onto the CM4 eMMC (factory reset), used to recover a broken installation.

A full OS reflash can only be done over USB: the CM4 must enter mass-storage-gadget mode via rpiboot, and you cannot rewrite the running rootfs from the device itself. Remote (WiFi) OS reflash would require an A/B / recovery mechanism on the OS side - see docs/ota-recommendation.md.

UX

One screen, one flow:

1. Plug the Reachy Mini (CM4) via USB - it is auto-detected.
2. Click Flash Reachy Mini.
3. Watch the progress (image download if needed, then flashing).
4. Done - unplug and reassemble.

How it works

• Detect (detect.rs): a Reachy is recognized either as a mass-storage disk (RPi-MSD / Compute Module / File-Stor signature) once its eMMC is exposed, or in USB download mode (Broadcom vendor id 0x0a5c) via nusb.
• Prepare (rpiboot.rs): when the CM4 is in download mode (eMMC not yet exposed), the app runs rpiboot -d mass-storage-gadget64 elevated to load the mass-storage bootcode, mirroring the manual procedure. The eMMC then appears as a disk and detection flips to ready.
• Image (images.rs): the OS image is resolved automatically - newest *.img(.gz) in the local cache, otherwise downloaded from the latest pollen-robotics/reachy-mini-os GitHub release (with a matching .bmap).
• Flash (flash.rs): bmap-parser sparse write + verify, with on-the-fly gz decompression. Raw disk writes run in an elevated copy of the app (flash-worker subcommand, macOS admin prompt / Windows UAC); the GUI tails a progress file.

Development

npm install
npm run tauri:dev     # run the desktop app
npm run build         # typecheck + build the frontend

rpiboot (required for real hardware)

Exposing the eMMC needs rpiboot + the mass-storage-gadget64 boot files from raspberrypi/usbboot. Fetch/build them:

./scripts/fetch-rpiboot.sh   # macOS/Linux: clones, builds, stages artifacts

Then, for dev, point the app at them:

export REACHY_RPIBOOT_BIN="$PWD/src-tauri/binaries/rpiboot/rpiboot"
export REACHY_RPIBOOT_DIR="$PWD/src-tauri/binaries/rpiboot/mass-storage-gadget64"

For production, bundle the folder by adding to src-tauri/tauri.conf.json:

"bundle": { "resources": { "binaries/rpiboot": "rpiboot" } }

On Windows, install the RPiBoot GUI (rpiboot_setup.exe) and copy rpiboot.exe + mass-storage-gadget64 into src-tauri/binaries/rpiboot/.

Simulation mode (test without a robot or root)

Set REACHY_FLASHER_SIM=1 to fake a connected Reachy, generate a small local image and flash it to a temp file - no hardware, no network, no admin prompt. The full detect -> flash -> progress -> done flow runs end to end.

REACHY_FLASHER_SIM=1 npm run tauri:dev

Safety

Raw disk writes are dangerous. The target is always the detected Reachy mass-storage disk (never the host system disk), and real writes require an explicit OS privilege prompt.