Didj 2.6.31 Generic Buildroot

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Revision as of 23:55, 25 February 2013 by Jrspruitt (talk | contribs) (Prerequisites)
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Buildroot is a build environment for making a Rootfs and Kernel. The Rootfs can be configured from a make menu allowing you to easily choose various applications. The Kernel was modified from the 2011-12-15 Releases, which includes several modifications to remove LeapPad1 Explorer and Leapster Explorer hardware specific code. To deal with the Didj's slider volume control, LFD, an included package in the sources was modified to apply changes to the volume as input requires.

This firmware will set you up with Avahi, for zero config networking and sshd. Also included are ncurses and Python with pyGame. Which could be used for some quick and easy app launching as there is no GUI included, only console on start up.

!!Warning!! This could potentially brick your device, but once Emerald Boot is installed, assuming you don't over write it, you should have an easy retry, should something go wrong.


Software Needed

Installing Buildroot

On your host PC use git, or download and extract the archive to your chosen location. Moving Buildroot after it has compiled the toolchain may be problematic, so choose a good location now. I prefer opt/buildroot myself.

git clone https://github.com/jrspruitt/OpenLF-Buildroot.git


wget https://github.com/jrspruitt/OpenLF-Buildroot/archive/master.zip


This will build you a Kernel zImage and rootfs.ubi to use when installing with OpenLFConnect. The first time you compile, can take a lot of time, as Buildroot compiles the toolchain. Once that is built, compiling takes considerably less time. It is good to choose your packages first and wisely, as Buildroot allows you to add packages, but requires a full rebuild to remove any. See Buildroot docs for more information.

There are two places to choose options for your Rootfs. As it stands it is fairly bare bones, except for Python with pyGame, and ncurses.

  • make menuconfig, this command brings up the Buildroot options, 'Package Selection' is where you will find various packages to install in your device's Rootfs.
  • make busybox-menuconfig, you will find even more options here.

The Kernel uses a patch file applied to the vanilla sources during the build. So if you plan on doing any Kernel hacking, its best to set up some vanilla sources alongside your LF sources so you can make a patch to use in Buildroot. Also study the included patch, as a Didj volume driver was included, along with several other changes. Admittedly this is kind of cumbersome, experience with Buildroot may yield some productivity enhancements here.

For advanced users of Buildroot, there is a board/OpenLF/Didj directory, where you can find the Kernel patch, various defconfig files, and the post build script files used during the build. Please refer to the Buildroot documentation for further explanation of these configurations.

Now that you have everything selected run:

$ make

If everything went correctly you should find your Kernel and Rootfs in [Buildroot dir]/output/target/images/ a zImage and rootfs.ubi file. Before installing you'll need to rename rootfs.ubi, to erootfs.ubi so OpenLFC can find it, when uploading both at the same time. You will also need a copy of bulk.ubi, the empty version from LF to utilize the rest of the NAND for storage. Copy this into the directory with your kernel and rootfs images.

Uploading Firmware

Using OpenLFConnect, after you've installed Emerald Boot, you'll need to set the Didj into USB Boot Mode. Hold both shoulder buttons and the ? button while turning it on.

Boot surgeon:

local> surgeon_boot /path/to/surgeon.cbf



Set custom partitions to use:

remote>dftp_update_partitions openlf.cfg

Change directory:

remote> cd /[Buildroot dir]/output/target/images/

Wrap zImage in CBF structure:

remote> cbw_wrap high kernel.cbf zImage

Update firmware:

remote> dftp_update

Reboot and disconnect:

remote> dftp_reboot

This should reboot your device, if not, cycle the power. At which point you should see a Tux logo followed by a command line prompt. You now have a basic Linux set up ready to go, waiting for you to develop something useful for it. The warm module for GPSP Emulator has been built into the Kernel if you'd like to start there.