That's not entirely true. The syslinux class does indeed a lot of this, I was able to experiment with this using the live hddimage. However, this mechanism ends up creating 2 different partitions, one containing the bootloader, and one containing the rootfs. I would like to have them in the same partition. I was able to find how to do it by scripting, but it's outside of the build environment. My script looks like this: