#Build a Debian Wheezy root filesystem

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		This article illustrates how to build an Debian Wheezy root filesystem for 
		the all the Acme Systems boards based on Atmel MCU 
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This article is not valid with the latest Ubuntu versions. Please follow this 
article: @article='debos'
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##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

<i>"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."</i>.

Create a working directory in your home directory:

	mkdir multistrap
	cd multistrap

Download the right multistrap configuration file for your board:

* [multistrap_roadrunner.conf](./multistrap_roadrunner.conf)
* [multistrap_acqua.conf](./multistrap_acqua.conf)
* [multistrap_aria.conf](./multistrap_aria.conf)
* [multistrap_arietta.conf](./multistrap_arietta.conf)

Read [Multistrap man page](https://wiki.debian.org/MultistrapManPage) 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:

<img src="./configuring_dash.jpg"/>

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:

* Roadrunner [roadrunner.sh](./roadrunner.sh)
* Acqua [acqua.sh](./acqua.sh)
* Aria [aria.sh](./aria.sh)
* Arietta [arietta.sh](./arietta.sh)
* FOX board G20 [fox.sh](./fox.sh)

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](/microsd_format). 

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](/DPI) to see the Kernel bootstrap
messages and boot.

##Related links

* [Multistrap](http://wiki.debian.org/Multistrap)
* [Multistrap man page](http://wiki.debian.org/MultistrapManPage)
* [Building a small Debian root filesystem with Multistrap](http://free-electrons.com/blog/embdebian-with-multistrap/)
* [QEMU User Emulation](http://wiki.debian.org/QemuUserEmulation)
* [Debian mailing list](http://lists.debian.org/debian-embedded/)
* [foreign debian bootstrapping without root priviliges](http://blog.mister-muffin.de/2011/04/02/foreign-debian-bootstrapping-without-root-priviliges-with-fakeroot,-fakechroot-and-qemu-user-emulation/)
* [Changing your locale on Linux and UNIX systems](http://publib.boulder.ibm.com/infocenter/wmbhelp/v7r0m0/index.jsp?topic=%2Fcom.ibm.etools.mft.doc%2Fae19494_.htm)
* [Locale](http://en.wikipedia.org/wiki/Locale)