PaceOS for the Amazfit Pace
PaceOS is a new operating system for the Amazfit Pace running watch (A1602/A1612). It is built on Linux and the LVGL graphics library and replaces the stock system, which is based on Android 5.1. The aim: a fast running watch that works like a Garmin and has features other watches keep for more expensive models or subscriptions.
Why
The Pace has good hardware: GPS, an optical heart-rate sensor, Wi-Fi, Bluetooth, a touch screen that is readable in sunlight, and one button. Its stock system is Android from 2015. PaceOS replaces it with a small system that mainly does one thing: measure and analyse your runs well, save them as standard FIT files and upload them where you want.
No accounts and no telemetry. The watch talks only to the services you set up, and now and then asks for a new version (exactly what it sends).
What it does
Everything below is written and tested in an emulator and with automated tests. On a real watch, PaceOS live runs so far (from RAM, not installed), and the basics are verified: the display, the button, Wi-Fi, Bluetooth, GPS reception and the battery reading. An outdoor run with GPS, heart rate and battery life are not verified on the watch – see Install.
Running
- Run, Trail, Treadmill and Walk profiles. On the treadmill the GPS is off and distance comes from steps times the stride learned outdoors.
- Garmin-style controls: press = next page, double press = lap, hold = pause with a menu (resume, save, back to start, discard).
- Data pages per profile: up to 6 pages of 1–4 fields, plus the map and music.
- Auto lap and auto pause, pace and heart-rate alerts, a drink reminder.
- A touch lock while running: neither rain nor a sleeve presses anything.
- Phone notifications by a policy (default: calls and texts only), quiet hours.
- FIT files as Garmin's SDK expects them. A run is saved as it goes; if the battery dies you lose at most the last 30 seconds.
Training
- A Training page after every run: load, recovery time, minutes per zone, heart-rate drop after 1 and 2 minutes.
- VO2max (from steady stretches only), records for 1, 5, 10, 21.1 and 42.2 km, the 7/42-day load ratio, a 5 and 10 km prediction, training status.
- A new maximum heart rate when you hold one for 30 s – offered by the watch, saved only when you tap it.
- Structured workouts in steps (warm-up, reps, recoveries, cool-down) with target paces.
- Planned workouts from intervals.icu on the watch.
- Uploads to Strava and intervals.icu over Wi-Fi.
Navigation
- Courses from GPX (Mapy.cz, Strava, Garmin Connect, Komoot, gpx.studio).
- Turn prompts ahead of a turn and at it, off-course alerts, back on course and finish.
- Back to Start along your own track, or in a straight line.
- The map shows your track and the course. There is no base map and no compass.
Coach
- A daily suggested workout: rest, recovery, easy, long, tempo, threshold, VO2max intervals or strides – with a reason and paces.
- 80/20, a long run once a week, respect for recovery and load, a taper before a race.
- A virtual pacer: a target time for a distance, or a pace; even or negative split.
- Performance condition during a run (once, between minutes 6 and 20) and a cadence metronome.
Music
- MP3s on the watch, played to Bluetooth headphones (the Pace has no speaker).
- Control of the phone's music through Gadgetbridge.
- A touch-controlled music page during a run.
Connect
- PaceOS Connect: set up the watch from a browser over USB, Wi-Fi or Bluetooth.
- Settings, data pages with a preview, Wi-Fi networks, Strava and intervals.icu accounts (passwords and tokens are write-only).
- Workouts with an editor, courses, run downloads, music uploads, updates.
- The phone through Gadgetbridge: notifications (a list, quick replies), calls (accept, reject, mute), find my phone, time, weather, music.
Updates
- Signed updates of the whole system into the other partition (A/B).
- The new system is tried first; if it does not come up, the watch goes back to the previous one by itself.
- A power cut while writing does no harm. The watch refuses older versions.
- From the watch (Wi-Fi) or from Connect; channel stable, beta or off.
Games
- Flappy, Dino, Stack, 2048, Snake, Breakout and Simon, each with its best score.
- Played with the button, taps or by dragging a finger.
What PaceOS does not have
- Calories: without the runner's weight they cannot be computed honestly.
- A base map and a compass.
- WPA3 Wi-Fi (the chip's driver cannot do it), EAP and WEP; WPA2 and open networks work.
- An installer for users – see Install.