This is an issue with the kernel that is used to boot the installation media. It is not built with the CD ROM drivers enabled. I’ve come access this with two of my hppa machines and this is common with the C8000 and 3750. It’s an ide driver for these machines that are not loaded.
There are two options available to you -
Put the missing firmware on media and load it when it fails to find the CD drivers.
Try the CD image from http://purple-cat.net/debian-hppa-cd/buster/
There will be install media created for the bullseye with the kernel complied with the CD rom drivers enabled. There maybe enabled in the current SID kernel on Debian Ports in which case you could try building a new install image.
Sent via my iPhone
On 11/03/2021, at 13:42, Christian Groessler <firstname.lastname@example.org> wrote: