Customizing NAND images

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HowTo [ID# 85843]  +/-

  For Developers

This document describes how to create a jffs2 image from a laptop's internal NAND, producing an image that can be flashed onto a different XO. The laptop that is being backed up is the "host" laptop, and the laptop receiving the contents of the host laptop is the "target" laptop.

If you instead want to create a new image from scratch, see Building custom images.

Basic Procedure

On recent Joyride (developer) builds, the sugar-control-panel can be use to change many setting, such as language. This may be sufficient for some customizations. For older builds, please follow the steps outlined below:

• Make the modifications on the host laptop that you want to be present in the generated image. If you've logged into Sugar and want the user to see the welcome/login prompt again, see the Section #Forcing Sugar to reprompt for name and colors. If you plan to use the image in laptops with different languages and keyboard layouts, you should delete also the file /.olpc-configured. This will force the system to run the olpc-configure script in the next boot.

• IMPORTANT: Make sure you delete these files in /etc/ssh:

ssh_host_dsa_key
ssh_host_dsa_key.pub
ssh_host_key
ssh_host_key.pub
ssh_host_rsa_key
ssh_host_rsa_key.pub

• Insert a Windows-formatted (VFAT) USB disk into the host laptop, and turn off.

• To restart hold the 'X' game pad key while pressing the power button. Type the "Esc" key at the "Type the Esc key to interrupt automatic startup"

• At the "ok" prompt, type "save-nand disk:\nand.img" and press return. The contents of the NAND will be backed up to the nand.img file on the USB disk. The "ok" prompt will return when the copy has finished, and you can then power the laptop off with the power button.

• Since build 406, you need a checksum file to successfully upgrade the system. To create the CRC file see the Section #Creating CRC file.

• Move to the "target" laptop, and insert the USB disk. Again, interrupt at the prompt, and at the ok prompt type "copy-nand disk:\nand.img". This will copy from nand.img to the internal NAND. When back at the ok prompt, power off, remove the USB disk, and power on again to load from the new NAND image.

Alternative method

• Download the tarball of a development image.
• Create a temporary directory, and change into it.

 mkdir img
 cd img

• Unpack the tarball while preserving numeric ownership. You will need to be root to do this.

 tar --numeric-owner -jxf olpc-*.bz2

• Make any modifications you wish to make. If you want to install an RPM, you can do it by chrooting:

 cp ../xxx.rpm .
 chroot .
 rpm -U xxx.rpm
 rm xxx.rpm
 exit

• Create a filesystem image. You will need the "crcimg" program from the pilgrim repository.

 mkfs.jffs2 -n -e128KiB -r img/ -o os123.pre
 sumtool -n -p -e 128KiB -i os123.pre -o os123.img
 crcimg os123.img
 rm os123.pre

• Put the .img and .crc files on a USB key, as described in Preparing the autoupdate image.

Example Customizations

Language

Sometimes you may want to define the default language for the system, either for use or while localizing.

Previously, we used /etc/sysconfig/i18n to define the LANG variable that Sugar will use.

In recent (Joyride) builds, this file has been ~/.i18n in order to move user-writable files to /home/olpc (See Olpc-utils). It can be changed using the Sugar Control Panel. The complete list of languages is in /usr/share/sugar/shell/controlpanel/control.py and also listed on the Sugar Control Panel page.

For example, the command to change to the Thai language:

sugar-control-panel -s language Thai

To Spanish (Mexico):

sugar-control-panel -s language Spanish/Mexico

To Brazilian Portuguese:

sugar-control-panel -s language Portuguese/Brasil

And back to English:

sugar-control-panel -s language English/USA

Note that you invoke these commands from the Terminal Activity; you must use Ctrl+Alt+Erase to restart Sugar in order to apply your changes.

Timezone

Timezone information is stored in the file /etc/timezone. For example, the east coast of the US is "America/New_York". This name references files found in /usr/share/zoneinfo, that control the system's timezone and daylight savings time behavior.

NOTE: if there is no 'timezone' file, then create one. If there is no file, the default is GMT.

Installing TrueType or OpenType Fonts

Either install as root prepackaged font package(s) from the Fedora repository as outlined below, or install the fonts in a subdirectory of /usr/share/fonts/ttf and run the fc-cache -f command afterwards.

XXX: fonts should be installed in /home/olpc/.fonts if they are to persist across upgrades. CScott 16:11, 27 September 2007 (EDT)

Activities

To remove an activity from the build, delete the desired directory from: /usr/share/activities:
rm -r TamTam.activity (for example)

To add an activity, install it in this same directory. Just unzip the .xo file to create /usr/share/activities/WhateverTheNameIs.activity/ .

(Note that individuals can download activities (.xo files) into /home/olpc/Activities from the web browser. This will load an activity onto the clipboard (and into the Journal) from which it can be installed and run.)

Keyboard

Localization

Sugar framework

Python framework

Localizing an XO

Keyboards

Changing language

Translators

Getting started

Website translation

modify

Note: There's currently no UI for customizing the keyboard. You have to use a text editor (like nano) and be very careful not to make mistakes: on security enabled laptops, it could be hard to recover from a bad keyboard configuration.

If the manufacturing data does not match the keyboard you need, you can set the keyboard type.

Since Ship.2, the keyboard configuration lives in /etc/sysconfig/keyboard:

 XKB_MODEL="olpc"
 XKB_LAYOUT="us,ru,kz"
 XKB_VARIANT="olpc2,olpc,olpc"

These settings can be overridden on a per-user basis by creating a file called /home/olpc/.xkb containing the same variables.

To change the symbol mapping of the keyboard, follow the following steps:

1. After the system has booted, press Ctrl+Alt+F1 (F1 is the same as the "mesh-view" key);
2. Login in as root (no password required);
3. Open the file /etc/X11/xorg.conf for editing (use vi, nano or any editor you are comfortable with);

Until build 623, these parameters used to be in /etc/X11/xorg.conf. Look for lines like these:

 Option "XkbModel"  "olpc"
 Option "XkbLayout" "us,ru,kz"
 Option "XkbVariant "olpc2,olpc,olpc"

Installing packages from the Fedora repositories using yum

Sugar is based off of Fedora and as such has a large amount of packages available to add to the base system. The tool used to do this is called yum. Because of memory constraints it is best to drop into run mode 3 which stops X. To do this log in as root either in the developer console or one of the virtual terminals and type this command:

init 3

X should exit and you should find yourself either at a login prompt or in the same virtual terminal. Log in as root if you are not already. To install or upgrade a package you simply use this command:

yum upgrade <package name>

To search for available packages you can use this command:

yum search <keyword>

More information about using yum with fedora can be found here.

Installing Flash, Java, MP3 codecs, MPEG4, patented codecs

These Restricted Formats have problems that makes it difficult or impossible for OLPC to preinstall, but you may be able and interested in deploying systems with these preinstalled.

(Note that the Adobe Flash plugin 9.0.31.0 is known to work and 9.0.60.120 is known not to work.)

Helix (Real) Media Player

The Helix media activity page covers installation of this activity and its associated codecs.

Forcing Sugar to reprompt for name and colors

You can always edit:

/home/olpc/.sugar/default/config

However, there may be times when you may want to force Sugar to prompt for a new name and colors as if with a new machine. You can do this by deleteing the configuration file and the SHH keys in the ./sugar/default directory.

rm /home/olpc/.sugar/default/config
rm /home/olpc/.sugar/default/owner.key
rm /home/olpc/.sugar/default/owner.key.pub

Note that:

1. This process does force the generation of new keys, which will potentially have (an adverse) impact on access to backup files on the school server.
2. The above process does not clean out the Journal data repository—the additional step of deleting the directory /home/olpc/.sugar/default/datastore will empty the Journal;

rm -r /home/olpc/.sugar/default/datastore

Other sugar state can be reset as well.

• The additional step of deleting the contents of the directory /home/olpc/.sugar/default/nm will clear the Network Manager database;

rm /home/olpc/.sugar/default/nm/*

• The additional step of deleting /home/olpc/.sugar/default/friends will clear the Friends database;

rm /home/olpc/.sugar/default/friends

Creating CRC file

First, you need to download and compile pilgrim

git clone git://git.fedoraproject.org/git/pilgrim
cd pilgrim/crcimg
make

File:Crcimg.sh - Linux crcimg executable
File:Crcimg.mm - Mac crcimg executable

After, you can from the command prompt create the crc from your custumized image

./crcimg myfile.img

Output is in myfile.crc