Building firmware

Loading firmware with a firmware development kit

Before attempting to flash, check the documentation for each board on how to prepare and connect your watch for programming.

You can flash the built firmware by running:

pbl flash

In some cases, you may have to specify the --tty $SERIAL_ADAPTER option where $SERIAL_ADAPTER is the path for your serial adapter, e.g. /dev/ttyACM0, /dev/tty.usbmodem1102, etc.

If flashing for the first time, you will also need to flash resources. Some boards support direct resource programming by passing the --resources option. The alternative is to flash while the firmware is running via the serial port using:

pbl image_resources --tty $SERIAL_ADAPTER

When both firmware and resources are flashed, you should observe the watch booting into the main application. You can also see the logs by opening the console:

pbl console --tty $SERIAL_ADAPTER

Try sending help to get a list of available console commands.

Loading firmware via Bluetooth

If you don’t have a firmware development kit, you may bundle a .pbz file for sideloading onto your sealed watch:

pbl bundle

The resulting .pbz file will be located in the build/ directory. Transfer this file to the device paired to your watch, then, in the Pebble app, enable Settings -> Show debug options. Go back to the Devices tab, tap your watch, then Firmware Update Debug -> Sideload FW, and select the .pbz file.

On Android, flashing repeatedly is better scripted over adb, which installs without asking. This route is open to an adb shell, which holds the android.permission.DUMP the broadcast requires, and it needs Show debug options on in the app. $PBZ is the file from build/:

adb push $PBZ /data/local/tmp/firmware.pbz
adb shell am broadcast -a coredevices.pebble.SIDELOAD_FIRMWARE \
    -n coredevices.coreapp/coredevices.pebble.firmware.FirmwareSideloadReceiver \
    --es path /data/local/tmp/firmware.pbz

The app waits up to a minute for the watch to be connected, then starts the update and shows its progress on the watch card in the Devices tab.

Not every Android version lets an app read /data/local/tmp. If the app reports the file as missing, create /sdcard/Android/data/coredevices.coreapp/cache and push it there instead.