Hi, the advantages of putting an unmodified ISO image plainly onto a USB are: - The boot and installation process is as near to DVD as possible. - If anything goes wrong during that process, it is clear that debian-cd is in charge of diagnosing and hopefully managing the effort to provide a correction.
Nevertheless, the goals of Pete are valid too: - A USB stick with large FAT partition is what many users expect. - The (unspecified by UEFI) way of copying EFI boot equipment and data payload into a FAT filesystem seems to be indeed the way how experienced users of MS-Windows prepare a bootable USB stick. - Copying from filesystem to filesystem is at least one order of magnitude less prone to fatal mishaps than is copying onto a device. Both approaches are combinable: - Have all EFI equipment as directory tree in the ISO filesystem. I.e. not only as image file or as appended partition. - Make sure that the installation works without name conflicts from a filesystem with sloppy naming rules. I.e. from FAT. And to promote my own song: Debian ISOs should strive for a specs compliant partition table with as few borderline hacks as possible. It would be fully compliant if bearing a MBR partition table with disjoint ISO and EFI partitions. But during the Ubuntu ISO reform there were problems with new Lenovos which booted only with GPT https://bugs.launchpad.net/ubuntu-cdimage/+bug/1886148 and with old HPs which are well known to boot only if some MBR partition bears the boot flag https://bugs.launchpad.net/ubuntu-cdimage/+bug/1899308 The Lenovo case is probably not fully explored, because it seems that the same machines boot from our current abominable MBR-with-invalid-GPT layout. The HP case needed a small hack by adding an MBR partition of type 0x00 and size 1 which bears the boot flag. I am not aware of failure reports with the Ubuntu 20.10 ISOs which could be blamed on their partition layout. Have a nice day :) Thomas
