Build a Debian Wheezy root filesystem

This article illustrates how to build an Debian Wheezy root filesystem for the all the Acme Systems boards based on Atmel MCU

Requirements

To create the rootfs contents you need an Linux PC with the some packages installed. Type these commands to install them:

sudo apt-get update
sudo apt-get install multistrap qemu qemu-user-static binfmt-support dpkg-cross

Use Multistrap to generate the rootfs contents

"Multistrap is a tool that automates the creation of complete, bootable, Debian root filesystems. It can merge packages from different repositories. Extra packages are added to the rootfs simply by listing them. All dependencies are taken care of.".

Create a working directory in your home directory:

mkdir multistrap
cd multistrap

Download the right multistrap configuration file for your board:

Read Multistrap man page to understand each directive meanings.

Create the root filesystem

When your multistrap.conf file is ready launch type:

if you are using a board without FPU (Floating Point Unit) like FOX Board G20, Aria G25 or Arietta G25 type for example:

sudo multistrap -a armel -f multistrap_arietta.conf

if you are using a board with FPU like Acqua A5 type:

sudo multistrap -a armhf -f multistrap_roadrunner.conf

At the end of this procedure the directory target-rootfs directory will contents the whole rootfs tree to be moved into the second partition of an Acme board bootable microSD.

Configure now the Debian packages using the armel CPU emulator QEMU and chroot to create a jail where dpkg will see the target-rootfs as its root (/) directory.

sudo cp /usr/bin/qemu-arm-static target-rootfs/usr/bin
sudo mount -o bind /dev/ target-rootfs/dev/
sudo LC_ALL=C LANGUAGE=C LANG=C chroot target-rootfs dpkg --configure -a

At this prompt:

Reply with < No >.

Some other prompt will appear during the configuration. Reply to them as you like.

When finished the target rootfs will be almost ready to be moved on the target microSD but it still needs some last extra configuration file before using it.

Based on type board you are using select one of these script to create the the right configuration files:

launch the script:

chmod +x roadrunner.sh
sudo ./roadrunner.sh

create now the target root login password:

sudo chroot target-rootfs passwd
Enter new UNIX password: [type your password]
Retype new UNIX password: [type your password again]
passwd: password updated successfully

If you want to take a look to the packages installed type:

sudo chroot target-rootfs dpkg --get-selections | more

Check the Debian version:

cat target-rootfs/etc/debian_version

Add more packages if needed by typing:

sudo LC_ALL=C LANGUAGE=C LANG=C chroot target-rootfs apt-get install [packagename]

Please note that will be possible to add packages also directly on the target board. In than case the command will be simply:

apt-get install packagename

then remove the qemu-arm-static executable:

sudo rm target-rootfs/usr/bin/qemu-arm-static

Copy the rootfs contents on microSD

Format a new microSD.

Mount the microSD on your Ubuntu Linux PC and copy all the target-rootfs contents in the second microSD partition mounted on /media/$USER/rootfs.

sudo rsync -axHAX --progress target-rootfs/ /media/$USER/rootfs/

Unmount the microSD, insert it in your board, insert the DPI cable to see the Kernel bootstrap messages and boot.

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