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Dextrose build system

Dextrose uses olpc-os-builder, a tool create by OLPC to build official and customized system images. The Dextrose git repository contains, olpc-os-builder, local customizations specific to Dextrose, and fixes and enhancements waiting to be pushed upstream.

Build host requirements

The Dextrose build system runs on Fedora 11 i386 through Fedora 14 x86_64. What the host system runs shouldn't matter, because the build runs in a chroot environment. olpc-os-builder does not yet run on Ubuntu due to a missing dependency (bitfrost).

The initial build requires about 700MB of rpm packages and Sugar activity bundles. The packages and bundles are cached for futures builds.

Initial setup

  • Install dependencies (you need to be root to do this)
 yum upgrade
 yum install libtomcrypt-devel bitfrost make gcc mtd-utils python-imgcreate zip unzip zlib-devel
  • Checkout Dextrose build system
 git clone git:// dextrose
  • Compile build helper programs
 cd dextrose
  • Generate initial sequence number for the builds (42 is just an example)
 echo 42 >buildnr-dx

Creating a build

  • Run the build system as root:
 time sudo ./ examples/dextrose2-xo1.ini

(if sudo isn't configured for your user, become root beforehand)

The initial build may take several hours, depending on available bandwith. Subsequent builds will take about 15-20 minutes on average machines.

Upon completion the new image will be available in build/output.

Because several build tools (olpc-os-builder, imgcreate and yum) run chrooted and nested into each other, error output could be misleading or obscure. Before digging into code, you can ask on IRC in case someone has already seen the same problem.

Publishing the images

Please do not publish signed builds unless they implement the OLPC anti-theft system.

Customizing your build

olpc-os-builder is documented at README in the olpc-os-builder tree. The modules are documented in README files in the modules directory.

Upstream Code

Dextrose is based on upstream olpc code located at

git remote add olpc git://
git fetch olpc
git log olpc/master

Customizing the core RPMs

  • Go to the rpms/PACKAGENAME in the dextrose tree
  • Edit the spec file. Typically this involves adding a new patch, which is done by adding a PatchNN: tag and a corresponding %patchNN rule in %setup. Some of the intricacies of RPM spec files are unveiled in the Fedora Packaging Guidelines.
  • Increase the release number after each change.

building the Custom RPM

If you have a Fedora 11 i386 system, just type:

 make i586

Otherwise, you need to build in a mock chroot:

 make srpm
 sudo mock -r fedora-11-i386 --resultdir=. --rebuild mypackage.src.rpm

Uploading the Custom RPM

  • Upload rpm to a yum repository and add it to the ini file used by the OLPC OS builder.
  • To automate this step, we have a rule make uploadrpm which points at the Dextrose repository. Edit rpms/common/Makefile.common or rpms/common/uploadrpm to retarget this rule to your repository.

Building custom kernels

$ git clone
$ cd olpc-2.6
$ setarch i386 make ARCH=i386 xo_1-kernel-rpm


  • RPM - The RedHat package manager
  • ASLO - The Sugar Labs Activities Library
  • General understanding of the Linux system plumbing infrastructure: kernel,

udev, dbus, DeviceKit, NetworkManager, Xorg...

  • Flashing laptops and debugging any problems
  • Interaction with the Sugar and OLPC community to solve issues and minimize our divergence from the official builds.