Opens (or installs) nRF Connect for Mobile — the app cannot be pre-filled from a link, so in it:
Advertiser tab → + → Add record → Complete List of 128-bit Service UUIDs → paste →
Connectable off, Advertising extension off (legacy), 100 ms, TX high → toggle ON.
Devices leave BLE mode 10 s after the beacon stops.
2 · Device
waiting for advertisement…
Load state
spec says ms; firmware field is named seconds — watch how long it flashes