Create Ubuntu root file system

Preparatory work

Install qemu

Install emulator on Linux PC host:

sudo apt-get install qemu-user-static

Download and extract ubuntu-core

The ubuntu root file system is based on Ubuntu base 16.04. Users can go to ubuntu cdimg to download, choose to download ubuntu-base-16.04.1-base-arm64.tar.gz.

After downloading, create a temporary folder and unzip the root file system:

mkdir temp
sudo tar -xpf ubuntu-base-16.04.1-base-arm64.tar.gz -C temp

Modify the root file system


  • Preparatory network:

sudo cp -b /etc/resolv.conf temp/etc/resolv.conf
  • Preparatory qemu:

sudo cp /usr/bin/qemu-aarch64-static temp/usr/bin/
  • Enter the root file system for operation:

sudo chroot temp

Update and installation

  • Update:

apt update
apt upgrade
  • Install the functionality you need:

apt install vim git ....(Add as needed)
  • Install xubuntu

apt install xubuntu-desktop
  • Errors may occur:

E: Unable to locate package xxxx

Installation package source is not added to the /etc/apt/source.list, lead to can’t identify the installation package, can add source by oneself, also can use the following given source.list covered the original /etc/apt/source.list file:

# See for how to upgrade to
# newer versions of the distribution.

deb xenial main restricted
deb-src xenial main restricted

## Major bug fix updates produced after the final release of the
## distribution.
deb xenial-updates main restricted
deb-src xenial-updates main restricted

## Uncomment the following two lines to add software from the 'universe'
## repository.
## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu
## team. Also, please note that software in universe WILL NOT receive any
## review or updates from the Ubuntu security team.
deb xenial universe
deb-src xenial universe
deb xenial-updates universe
deb-src xenial-updates universe

## N.B. software from this repository may not have been tested as
## extensively as that contained in the main release, although it includes
## newer versions of some applications which may provide useful features.
## Also, please note that software in backports WILL NOT receive any review
## or updates from the Ubuntu security team.
deb xenial-backports main restricted
deb-src xenial-backports main restricted

deb xenial-security main restricted
deb-src xenial-security main restricted
deb xenial-security universe
deb-src xenial-security universe
deb xenial-security multiverse
deb-src xenial-security multiverse

Add user and set password

  • Add user:

useradd -s '/bin/bash' -m -G adm,sudo firefly
  • Set the password for user:

passwd firefly
  • Set the password for root:

passwd root
  • Modify your root file system can exit:


Make the root file system

Make your own root file system, depending on the size of your root file system, and note that the count value is modified based on the size of the temp folder:

dd if=/dev/zero of=linuxroot.img bs=1M count=2048
sudo mkfs.ext4 linuxroot.img
mkdir  rootfs
sudo mount linuxroot.img rootfs/
sudo cp -rfp temp/*  rootfs/
sudo umount rootfs/
e2fsck -p -f linuxroot.img
resize2fs  -M linuxroot.img

linuxroot.img is the final root file system image file.


Q: After the root file system is loaded, the size is not normal and does not occupy the entire partition?

A: Execute the extended file system command after the system is loaded correctly:

 resize2fs /dev/mtd/by-name/linuxroot