Setup

1. Installation

git clone https://github.com/arnav-kr/cmf-cmf-watch-utils.git
cd watch-utils
uv sync

This creates a virtual environment with the fwkit CLI and the BLE tool dependencies. The installation is verified with:

uv run fwkit --help
uv run python tools/cmf_watch.py --help

2. Firmware image

The stock image for this device is published under dumps/binaries/:

git lfs pull --include="dumps/binaries/firmware/JX402_V1.0.0.73.bin"

A local copy is used for editing, and the firmware/ directory is gitignored:

firmware/JX402_V1.0.0.73.bin

The image is parsed and verified before any edit or flash:

uv run fwkit info firmware/JX402_V1.0.0.73.bin
uv run fwkit verify firmware/JX402_V1.0.0.73.bin

3. Watch advertising

With the watch disconnected in the Nothing X / CMF app, or phone Bluetooth turned off, the watch advertises as CMF Watch Pro 2-XXXX. The advertised device is located with:

uv run python tools/cmf_watch.py scan

4. Pairing and local auth state

uv run python tools/cmf_watch.py pair

The command performs the full pairing exchange and writes tools/.watch_state.json. The file holds the watch secret and authkey — it is never committed or shared. After a factory reset, or after the factory-menu shutdown/reset option is used, the watch is re-paired; a stale authkey can still get an A052 reply but will not enter the OTA data phase.

5. Read-only check

uv run python tools/cmf_watch.py info
uv run python tools/cmf_watch.py ota-state --duration 5

Correct version, battery and PID values indicate a working BLE path. Firmware flashing is a later step.

Documentation site

Required only for documentation work:

cd site
pnpm install
pnpm dev