Reading from ISO9660 in U-Boot

[Heinrich Schuchardt]

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.

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

Best regards

Heinrich