Booting the Capri AP board using a Mainline or LT kernel

Board Configuration

  • Plug in the DC power to the 5VDC barrel jack
  • Using a USB-A to USB-micro-B cable, connect the host system to the USB-micro-B jack marked USB DBG. The FTDI driver on the host will enumerate 4 different TTYs. The first of these will be the debug UART that is used for the console.
  • Using a USB-A to USB-micro-B cable, connect the host system to the USB-micro-B jack marked USB OTG. This connection will be used for flashing images using the fastboot tool.
  • SW1009, near the DC barrel jack, is the power switch. Slide it to on and the board will power up


You will need the fastboot tool which is part of the android-tools-fastboot package for Ubuntu users.

You must update your udev rules or run fastboot as root.

Build a Kernel

Check out the mainline Linux kernel or the llct/capri-support branch in the LT public tree.

Build the kernel:

$ make ARCH=arm CROSS_COMPILE=arm-linux-gnueabi- bcm_defconfig
$ make ARCH=arm CROSS_COMPILE=arm-linux-gnueabi- zImage bcm28155-ap.dtb

Installing a new Kernel and Booting

This section assumes that the board already has a full set of images including the partition table, boot loaders, and the file system.

When powering up the board, use the serial connection and press any key during the U-Boot countdown then command the target to enter fastboot mode:

U-Boot 2013.01 (Nov 12 2013 - 15:29:56)

I2C:   ready
DRAM:  768 MiB
WARNING: Caches not enabled
Relocation Offset is: 11f84000
kona_mmc_send_cmd: waiting for status update
kona_mmc_send_cmd: waiting for status update
*** Warning - bad CRC, using default environment

In:    serial
Out:   serial
Err:   serial
Disabling watchdog
Hit any key to stop autoboot:  0
capri> fastboot

On the host system, verify that a fastboot device is visible:

$ fastboot devices
1234567890      fastboot

Flash the kernel and device tree built above:

$ fastboot flash kernel zImage
sending 'kernel' (2226 KB)...
OKAY [  0.267s]
writing 'kernel'...
OKAY [  0.663s]
finished. total time: 0.936s

$ fastboot flash device-tree bcm28155-ap.dtb
sending 'device-tree' (5 KB)...
OKAY [  0.003s]
writing 'device-tree'...
OKAY [  0.013s]
finished. total time: 0.018s

When you are done updating images, allow the Capri AP board to continue autoboot of the images:

$ fastboot continue

Capri Boot Instructions (last modified 2013-11-15 02:08:52)