The Pine Time is a hackable watch by Pine64. The default firmware is InfiniTime. To compile and upload from my Acer CB314 ChromeBook (aarch) there are some dependencies and steps. Most of the details are on the Infinitime GitHub pages.

git clone https://github.com/InfiniTimeOrg/InfiniTime.git
cd InfiniTime
git submodule update --init

Download arm toolchain and unpack (tar xvf <filename>) to InfiniTime directory. Download nRF5 SDK and unzip to InfiTime directory.

sudo npm install lv_font_conv sudo pip3 install adafruit-nrfutil

cd build
cmake -DARM_NONE_EABI_TOOLCHAIN_PATH=/home/brian/InfiniTime/gcc-arm-none-eabi-10.3-2021.10 -DNRF5_SDK_PATH=/home/brian/InfiniTime/nRF5_SDK_15.3.0_59ac345 -DBUILD_DFU=1 ..
make pinetime-mcuboot-app

The make process creates a zip containing the firmware image called, pinetime-mcuboot-app-dfu-x.y.z.zip in the src subdirectory of build directory where x.y.z are is the version. This needs to be transferred to the watch over Bluetooth using a companion app running on a computer or phone. I use Gadgetbridge on my Android phone because that is what is mostly connected to the watch. (The watch does not allow multiple Bluetooth connections.)

Install the apk image from FDroid as directed by the Gadgetbridge website.

I found it challenging to pair the phone with the watch but after some peseverence it worked. Do not pair using the Android Bluetooth screen - use Gadgetbridge. Ensure all permissions requested by Gadgetbridge are granted.

From Gadgetbridge, use the device menu to select "File Installer" then navigate to the firmware zip file and upload. I use Google Drive to host the file as it is simple to transfer from the ChromeBook and to the phone - both have access to Drive.