Customize alternate install CD with UEFI?

[Josef Wolf]

Hello,

I am trying to create a customized install CD based on
ubuntu-16.04-server-amd64.iso

According to http://www.syslinux.org/wiki/index.php?title=Isohybrid#UEFI I
need the isolinux/efiboot.img file to make this iso bootable with UEFI.

But there is no such file on the original ubuntu install CD. Where do I get
it?

While at it: the partitioner on ubuntu-16.04-server-amd64.iso don't seem to be
aware of the UEFI partitions?

What am I missing here?

-- 
Josef Wolf
jw at raven.inka.de