Bootloader is build with ArmTF and UEFI from sources located at:
device/linaro/bootloader
To build fip.bin and l-loader.bin do:
$ cd device/linaro/hikey/bootloader
$ make
Results will be in out/dist
We can also generate ptable (needs root privilege) with below commands:
$ cd device/linaro/hikey/l-loader/
$ make ptable.img