Hacking Linux for chumby
Existing Software
See existing Chumby Software Applications, Scripts and Tools already on your Chumby stock linux distro.
Alpha Prototype
The Alpha Prototype chumby runs a modified linux 2.4.20 kernel.
Compiling the Kernel
First, install the GCC Toolchain.
In order to build the chumby kernel, you can download the kernel source from chumby_kernel.tgz and build by doing the following:
# mkdir kernel # cd kernel # tar zxvf chumby_kernel.tgz # make menuconfig (then immediately exit and save the config) # make dep # make Image
If all goes well, you should end up with an uncompressed kernel image at arch/arm/boot/Image.
Ironforge
The "Ironforge" production chumby runs Linux 2.6.16 kernel.
First install the GNU Toolchain
In order to build the chumby kernel, you can download the kernel source from linux-2.6.16-chumby-1.0.tar.gz and build by doing the following, NOT as root, but as a normal user.
$ mkdir kernel $ cd kernel $ tar zxvf linux-2.6.16-chumby-1.0.tar.gz $ cd linux-2.6.16 $ cp arch/arm/configs/mx21ads_defconfig .config $ ARCH=arm BOARD=mx21ads CROSS_COMPILE=arm-linux- make oldconfig (select 'Y' when asked if you wish to build in the 224 color Turbochef logo) $ ARCH=arm BOARD=mx21ads CROSS_COMPILE=arm-linux- make
If all goes well, you should end up with a compressed kernel image at arch/arm/boot/zImage and all of loadable kernel modules under the drivers directory.
By default, there are only 3 drivers built with this configuration:
$ find drivers -name *.ko
Which should return:
drivers/char/chumby_accel.ko drivers/char/chumby_sense1.ko drivers/char/chumby_timer.ko drivers/mfd/chumby-tsc2100.ko
You might want to enable more modules to get the recommended:
# find drivers -name *.ko
Which should return:
drivers/media/video/cpia.ko drivers/media/video/compat_ioctl32.ko drivers/media/video/cpia_usb.ko drivers/media/video/v4l1-compat.ko drivers/media/video/v4l2-common.ko drivers/media/video/videodev.ko drivers/bluetooth/hci_usb.ko drivers/bluetooth/hci_vhci.ko drivers/video/console/bitblit.ko drivers/video/console/fbcon.ko drivers/video/console/fbcon_ccw.ko drivers/video/console/fbcon_cw.ko drivers/video/console/fbcon_rotate.ko drivers/video/console/fbcon_ud.ko drivers/video/console/font.ko drivers/video/console/softcursor.ko drivers/char/chumby_accel.ko drivers/char/chumby_sense1.ko drivers/char/chumby_timer.ko drivers/usb/media/dsbr100.ko drivers/usb/net/asix.ko drivers/usb/net/cdc_ether.ko drivers/usb/net/pegasus.ko drivers/usb/net/usbnet.ko drivers/usb/input/usbhid.ko drivers/mfd/chumby-tsc2100.ko
Flashing the Kernel
Directions provided by Bunnie in the forum: [1]
If you want to reflash the kernel image, the quickest way to do it is to take the zImage file, zip it, and copy it to a VFAT formatted USB disk, and put it in a directory called "update2" by the name of k1.bin.zip. Even though zImage is already compressed, you need to zip it again because of the way the firmware updater works. Then, power on the chumby while pressing the touchscreen, and continue pressing it until you get into special options. Select the menu option to update the chumby, and then select update via USB. This will take the kernel image on the USB disk and flash it into the device. You can completely destroy the k1.bin.zip image and recover from this, because this update mechanism uses its own copy of the kernel that is unaffected by the update to k1.bin.zip. If you want to add more apps, you need to build a cramfs filesystem, and use a similar procedure but name the resulting cramfs binary image rfs1.bin.zip, also stuck in the update2/ directory on the USB drive.