Re: isorecorder
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
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