How-to: Dual Boot Flint OS

Warning! Flint OS dual Boot is in beta, we cannot be held responsible for any data loss please backup your data before installing Flint OS.

Boot Flint OS for PC

These instructions apply to the Flint OS PC versions. The instructions require some knowledge of a linux environment. We will be providing a simpler GUI version in the near future.

System Requirements

  • 64-bit PC able to boot from a Flint OS imaged USB
  • Must have a device that uses UEFI (CSM mode can be enabled)
  • The hard disk is partitioned in GPT, with atleast 8GB of free space.
  • The remaining space on the hard disk needs to be in free space, not an unused partition.
  • Disable Fastboot within Windows power settings

In order to avoid the data loss caused by accidental deletion of the partition, the installation script does not delete any existing partitions, so the user is required to release and prepare enough free space.

Windows system instructions

You can use the Windows disk partition tool to shrink existing partition and free up the space required for the installation. You do not need to format the free space created as a partition.

MacOS instructions

The system comes with the Disk Utility tool to shrink existing partition, but the free space will be automatically divided into an “Untitled” partition.

You will need to use a different partition tool to remove the Untitled partition to get free space. This step can be done in the shell after starting Flint OS. Fdisk, gdisk, parted and other tools of your favorite can be used to complete this step.

Linux system instructions

If you use the Linux system, you should not require additional instructions :).

Installation process

Accessing the shell

Download the PC image from and burn to a USB as normal.

Start FlintOS and access the shell interface. Either of the following two ways:

After the graphical interface appears, press Ctrl + Alt + F2 to switch to the console and type “shell”


Enter guest mode to open the Chromium browser. Press Ctrl + Alt + T to enter the crosh interface. Enter the “shell” command to enter the shell.

The system chronos user password defaults to chronos or chronos..

The commands are run as root, you can execute the sudo command before each command, or you can get the root shell run directly after sudo -i.
Check system information

First you need to know the hard disk device name to install Flint OS. You can use the following command to confirm the system hard disk information such as size, the existing partition, etc.Fdisk -l

For most single hard disk systems, usually /dev/sda, if it is a second hard drive, it is /dev/sdb, and so on. The following example to /dev/sda, for example, please replace the actual situation of their own system input.

Install Flint OS to the hard disk

Run the following command -d /dev/sda

The installation script checks whether the system meets the requirements, whether the disk partition, and the remaining space meet the requirements, and then begins creating the files needed for partitioning and installation.
After the script is installed and installed correctly please restart the system, the rEFInd boot menu will appear where you can select Flint OS or your other OS.


How long does it take to install?

Under normal circumstances about 10 minutes, depending on the disk and USB boot device speed will have some fluctuations.

How many partitions will be created on the system

Will create 11 new partitions. Flint OS follows the Chromium OS standard, there will be 12 partitions, one of which is the ESP partition. Because the UEFI dual boot system already has a ESP partition in the partition table the script creates 11 new partitions. This is in accordance with the Chromium OS standard so that we may provide network updates automatically in the future.

Is the installation process safe? Will I lose data?

The installation process will do a few things:

  • Create the required partitions.
  • Write the necessary files for FlintOS to the newly created partition.
  • Copy some files to the ESP partition.
  • Add a system startup item.

The script does not do anything to delete an existing partition or empty the disk, partition table, and so on, so theoretically it is quite safe. Of course, at any time when you modify the disk remember to fully backup your data or use an unimportant hard drive to do the test. We will not be responsible for any loss of data caused by Flint OS.

How to uninstall

If you want to remove the boot menu, but are happy to leave Flint OS on the hard drive you can go to the motherboard BIOS (UEFI) settings interface, and change the boot order to default to your other OS.  This will then directly start the default OS of your choice not the dual boot interface.

If you want to completely uninstall and retrieve the space previously assigned to FlintOS, you will need to delete the rEFInd startup items, FlintOS installation will create 11 partitions which can be deleted.

A full hard disk wipe and reinstallation of your chosen OS will also remove the Flint OS dual boot setup.

Note: If you delete partitions that belong to your other OS you may cause system stability issues until you reinstall the OS.