Re: [Fwd: Re: isorecorder]
On Mon, 2021-01-11 at 02:21 +0000, Pete Batard wrote:
> On 2021.01.11 01:38, Lou Poppler wrote:
> > This is radically different from what I suggested above.
>
> You mentioned cp, which I interpreted as copying extracted ISO files
> onto FAT, since this is the mode I explicitly mentioned in my initial reply.
>
> > Here is my experiment:
> > lwp@william:~/Downloads$ wget https://cdimage.debian.org/cdimage/weekly-builds/amd64/iso-cd/debian-testing-amd64-netinst.iso
> > lwp@william:~/Downloads$ umount /dev/sdb1
> > lwp@william:~/Downloads$ sudo bash
> > root@william:/home/lwp/Downloads# cp debian-testing-amd64-netinst.iso /dev/sdb
> > root@william:/home/lwp/Downloads# sync
> >
> > At this point I moved the USB stick to a Toshiba amd64 laptop,
> > and booted with no problems into the installer.
> >
> > Notice especially that I did *not* copy the installer .iso onto a partition of the USB stick,
> > I copied the image to the bare USB i.e. /dev/sdb _NOT_ /dev/sdb1
>
> Which means that you are limiting ISOHybrid use to DD/byte-copy mode
> only, which is precisely what I am trying to warn against relying solely on.
>
> A *proper* ISOHybrid media should be able to be extracted to a FAT32
> formatted partition and boot in UEFI mode.
The media we are discussing, debian-testing-amd64-netinst.iso, as copied
to my USB stick and booted in BIOS mode on the Toshiba laptop, also boots
just fine on this dell amd64 box in UEFI mode.
I will stipulate that there may be other architectures or devices which do not
work the same as amd64 desktops/laptops. However, in all the varieties of
testing I have done on amd64 desktops/laptops, the direct byte-for-byte copying
of the installation image onto the base of a USB stick works properly in both
BIOS booting and UEFI booting. Perhaps more complicated schemes are needed
for other situations, I agree that is possible. I am only trying to explain
why I always suggest to amd64 users, on the general #debian IRC channel, that
they should directly copy the downloaded image to their USB stick with dd or cp
(as you saw in my example previous) or with rufus's DD mode. In this standard
situation, any other method of writing the USB stick causes hard to debug
problems.
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