Research best practices in ISO layout

[mika]

We should research whether the way our ISOs are generated with xorriso, isohybrid etc are still all follow best practices of year 2020.

Thomas Schmitt wrote a great summary in https://lists.debian.org/debian-cd/2019/07/msg00007.html (restumbled upon it via a recent discussion in https://lists.debian.org/debian-live/2020/03/msg00213.html) and there's a reference also at https://wiki.debian.org/RepackBootableISO

What I'm also interested in is a nice way to make our ISOs more customization-friendly, especially when having the need to add further partition(s) to a USB stick when dd-ing the Grml ISO onto it (without having to use grml2usb and having to manually deal with the appropriate partition layout).

FTR: we're interested in amd64 and i386 architectures only, though would like to have the system boot on as many systems as possible out of the box (BIOS, EFI + SecureBoot).

[mika]

Further interesting reads are https://wiki.syslinux.org/wiki/index.php?title=Isohybrid + https://lists.debian.org/debian-knoppix/2018/10/msg00002.html