Initialize the environment with the envsetup.sh script. Assuming you
are at the top of the Android source tree:
    $ export TOP=`pwd`
    $ . build/envsetup.sh

Choose target.
    $ lunch aosp_ci20-userdebug

Build everything.

- UBIFS:
    $ make -j24

- EXT4:
    $ make WITH_EXT4=true -j24

Generate an SDCARD image containing the Android compatible u-boot and
Android boot/recovery/system images.

    $ cd $TOP/device/imgtec/ci20/sdcardinstaller
    $ ./mksdcard /dev/sdX

Install Android on CI20. Set the JP3 link to 2-3 to enable boot from
SDCARD. Install the SDCARD and powercycle the board. u-boot will
start up and automatically reformat the flash and install both u-boot
and Android to it. After it has completed you should see something
like:

> 134217728 bytes read in 19742 ms (6.5 MiB/s)
> 134217728 bytes written to volume system
> 9338880 bytes read in 1440 ms (6.2 MiB/s)
> 9338880 bytes written to volume system
> All done :)

After the Android installation is complete it is possible to boot
Android from NAND by setting the JP3 link to 1-2 and power cycling the
board. If the JP3 link is left in 2-3, and the board is power cycled
Android will also boot, but the boot.img file will be read from the
SDCARD. This can be convenient when testing changes for the kernel or
root filesystem.