So, I'm trying to include a custom u-boot and kernel into my layer.

What i have: My supplier probably did something like this:
$bitbake -c unpack virtual/bootloader
copied that entire folder to supplier_uboot and added some new files for their board, made a script that creates u-boot_customboard.imx

My question:
What do i need to do, in order to use that specific folder and make sure it creates that custom u-boot?

My two ideas so far:
a: create recipes-bsp/u-boot and recipes-kernel in my own meta-layer and just use the dts files and u-boot_customboard.imx with a new MACHINE

b: Create a git repo with suppliers changes and create recipes that uses that, but then again, how do i create an u-boot recipe that uses custom settings?