Fetch Linux sources:

$ cd $WD
$ git clone git://github.com/ntb-ch/linux
$ cd linux
$ git branch
* efs
$ git describe
Apalis_iMX6_LinuxImageV2.3Beta6_20150112-1-g879d496

Configure and build Linux:

$ make colibri_imx6_defconfig
$ time make
$ make UIMAGE_LOADADDR=0x10008000 uImage
$ make modules
$ make modules_install INSTALL_MOD_PATH=../modules/