This is what I do:

step 1: download image http://releases.linaro.org/13.10/ubuntu/panda/panda-raring_developer_20131021-500.img.gz

           and flash it to my SD card. test it on pandaboard, run well.

step 2: setup toolschain with http://releases.linaro.org/13.04/components/toolchain/binaries/gcc-linaro-arm-linux-gnueabihf-4.7-2013.04-20130415_linux.tar.bz2

step 3: download kernel source code from http://releases.linaro.org/13.10/components/kernel/linux-linaro/linux-linaro-3.12-rc5-2013.10.tar.bz2,  uncompress to dir kernelSrc   cp  SdCard/rootfs/boot/config-3.12.0-1-linaro-omap  kernelSrc/.config

step 4: cd kernelSrc

           LOADADDR=0x80008000 make ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf- uImage -j8

           copy arch/arm/boot/uImage  to SdCard/fat32partion/ replace the offical uImage

step 5: test the SD card again, run failure. the console message stop on

            Starting kernel ...

Could you help me,    How to rebuild the ubuntu kernel correctly?