If your PI is older than this(the last year ) then ...
it should possible to update the older picore images /boot partition
with updated firmware files that include support for the latest hw
in fact hear is a script to do that & more github.com/Hexxeh/rpi-update/blob/master/rpi-update#L187
all though it is intended to run on raspbian !
reading it might provide some hints , eg the update_firmware function
--
with the above in mind
perhaps the most critical part of : Getting started building pi distro?
is booting the pi , for this the [ 0 ] firmware is required to do hw initialization
0 -
https://github.com/raspberrypi/firmware/tree/master/boot 0.1 -
https://github.com/Hexxeh/rpi-firmware <-- repo just for boot files
so imho! wrt to pi hw and building distro
step 0) is create a simple disk image and "boot" partition and add the firmware ; then test that this just firmware image can boot ! on your hw.
step 0.0 ) compare firmware configuration files from different raspberry pi distribution images ...