Building a custom kernel for the DE1-SoC...

Yup, bang on reply; I have successfully built and run a kernel now - thank you very much.

It just goes to show that RTFM has value ;).

Great. I now have a kernel - what I really want is to boot from my new kernel into my Ubuntu release.

I notice from the .config where the rootfs is being built

CONFIG_BLK_DEV_INITRD=y
CONFIG_INITRAMFS_SOURCE="../rootfs.cpio.gz"

and thought it would be a breeze to expand the newly built zImage and drop in the corresponding rootfs from the Ubuntu zImage - but it's not that simple.

I have spent a fair few hours trying to be clever and in humility would like some help please on getting my new kernel to boot Ubuntu. Ideas on a postcard please ;).

Thanks again and I very much look forward to your reply.