build_image: Add building minios initramfs kernel

And writing the kernel into the MINIOS-A partition of the disk
image. This allows us to move forward with the rest of the minios
implementation including signing, paygen, updates, etc.

TEST=./build_image --board zork-minios test

Cq-Depend: chromium:2872568
Change-Id: I9fac016f8e43160a49961b5209650ffd565e2996
Tested-by: Amin Hassani <>
Reviewed-by: Chris McDonald <>
Commit-Queue: Jae Hoon Kim <>
1 file changed