Reading from ISO9660 in U-Boot

[Simon Glass]

Hi Heinrich,

On Fri, 22 Sept 2023 at 19:38, Heinrich Schuchardt <xypron.glpk at gmx.de> wrote:
>
> On 9/23/23 00:13, Simon Glass wrote:
> > Hi Heinrich & Bin,
> >
> > I'd like to be able to figure out in U-Boot what OS is on a USB stick.
> > For example, with the Ubuntu installer, I can boot it (through grub),
> > but I cannot see how to read anything useful from the USB stick that
> > would indicate that it is Ubuntu, what version it is, etc.
> >
> > Does U-Boot need an ISO9660-filesystem driver for that? Is there any other way?
> >
> > With Debian I can see the actual files (linux and initrd) , so it is a
> > bit easier.
> >
> > Regards,
> > SImon
>
> U-Boot only needs to support reading the ESP to boot. GRUB comes with a
> 9660 driver.

Yes, but this is not about booting, it is about visibility into what
is being booted. Perhaps Ubuntu could put some information in
partition 2?

>
> On Ubuntu server installer images linux and initrd are in directory
> casper/ in the ISO9660 file-system.
>
> There is also a file dists/mantic/Release
>
> $ cat dists/mantic/Release
> Origin: Ubuntu
> Label: Ubuntu
> Suite: mantic
> Version: 23.10
> Codename: mantic
> Date: Tue, 19 Sep 2023 23:07:01 UTC
> Architectures: amd64 i386
> Components: main restricted
> Description: Ubuntu Mantic 23.10
> Acquire-By-Hash: yes
>

That would be useful info. Ideally we would have a standard format for
this file across all distros, perhaps something that VBE can help
with.

Regards,
Simon