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
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
and with old HPs which are well known to boot only if some MBR partition
bears the boot flag
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 :)