Build and pave quickstart

This document shows you how to build and deploy Fuchsia on a target device with fx development commands. Most of these commands have additional commands, see fx help <command> for details.

Determine USB drive device path

Before you attempt to build and pave Fuchsia on a target device, you need to know the path of your USB drive.

Note: For either operating system, you can run the command once with the USB drive disconnected, then run again with the USB drive connected, to see the difference.


To determine the correct path to your USB drive:

Note: The fx tool is platform agnostic and lists available USB drives.

fx mkzedboot


To determine the correct path to your USB drive:

sudo fdisk -l

Drives are usually in the form /dev/sd[x] such as /dev/sdc.

Make sure that you select the drive rather than a specific partition. For example, a specific partition has a number at the end of the path such as /dev/sdc1.


To determine the correct path to your USB drive:

diskutil list | grep external

Drives are usually in the form /dev/disk[n] such as /dev/disk2.

Note: If you see ERROR: Can't open /dev/disk[n]: Resource busy then you will have to unmount the USB drive. To do this, run:

hdiutil unmount /dev/disk[n]

If this does not fix the error, try reformatting the drive:

diskutil eraseDisk JHFSX <name_of_the_usb_stick> /dev/disk[n]

Build and deploy Fuchsia

To perform an initial build and deploy of Fuchsia with fx, do the following:

  1. Set your build type:

    Note: Configures the build to build the core product on a generic x64 board. For a list of available products and boards, see fx list-products and fx list-boards for lists of available products, respectively.

    fx set core.x64
  2. Build a Fuchsia image:

    fx build

    This command builds Zircon and then the rest of Fuchsia.

  3. Build the Zedboot media and install to a USB device target:

    Note: For information on obtaining the USB drive device path, see USB drive device path.

    fx mkzedboot <usb_drive_device_path>
  4. Attach Zedboot USB drive to your target device and reboot that device.

  5. On your target device, run:

  6. Take note of the HDD or SSD's device path from the output of lsblk. An example path looks like /dev/sys/pci/00:17.0/ahci/sata0/block.

  7. On your target device, run:

    install-disk-image init-partition-tables --block_device_path <BLOCK_DEVICE_PATH>
  8. To start the bootserver, from your host, run:

    Note: The bootserver connects to the target device to upload the Fuchsia image and then paves your target device.

    fx pave

Rebuild and redeploy Fuchsia

To rebuild and redeploy with fx:

  1. Ensure that HEAD is in a good state to pull at the build dashboard.

  2. Fetch the latest code:

    jiri update
  3. Build a Fuchsia image:

    fx build

    This command builds Zircon and then the rest of Fuchsia.

  4. (Only for macOS users) Set up firewall rules:

    fx setup-macos
  5. From your host, start a development package server:

    fx serve
  6. Boot your target device without the Zedboot USB attached.

  7. From your host, push updated Fuchsia packages to the target device:

    fx ota

    In some cases, if fx ota does not complete successfully, consider repaving with fx pave.


  • If fx build fails, make sure that your PATH environment variable is set correctly.

    Note: The fx script changes the working directory in a way that may create conflicts between the commands it uses (such as touch) and the binaries in the working directory.

    To check the value of your PATH variable:

    echo $PATH

    Make that sure that the output of your PATH variable is a list of directories separated by colons. Make sure that none of the directories are separated by ..