• Re: UEFI HTTP boot support in the Installer

    From Andrew M.A. Cater@21:1/5 to Computer Enthusiastic on Sun Jun 8 17:10:02 2025
    On Sat, Jun 07, 2025 at 12:02:21PM +0200, Computer Enthusiastic wrote:
    Hello,

    Really a nice job, thank you.

    I successfully started the http://cdimage.debian.org/cdimage/daily-builds/daily/arch-latest/amd64/iso-cd/debian-testing-amd64-netinst.iso
    using a QEMU VM with Tianocore EUFI firmware and a *local* HTTP server.

    I have a few questions about the UEFI HTTP boot support in the Debian Installer for the next stable release (Trixie):

    1) Will the Debian-testing-amd64-netinst.iso be the only Debian-installer
    ISO released for Debian Trixie with UEFI HTTP boot support?


    If you have reasonably fast 'Net connectivity then you probably don't
    need more than the netinst .iso. The installer is usually the same on
    each size of medium so it might work but you raise the issue of image
    size below.

    2) In the future, could it be reasonable to create a version of the Debian Installer ISO that is specifically reduced in size to support UEFI HTTP
    boot, making it suitable for installations on computers with 1.5 GB or less of RAM (the ISO image is loaded into memory and is currently 800 KB in size, leaving insufficient memory for the installer to work properly)?


    This is presumably the netboot install medium. Probably not worth trying
    to install a modern Debian on something with lower than 2GB memory anyway
    (see suggested hardware configurations in the release notes. I think 2GB
    is now an absolute minimum if you want a response from the machine that
    is usable).

    3) Does the Debian-Installer ISO need to be specifically crafted to be UEFI HTTP boot support compliant, other than adding pmem modules to the installer initrd and recognising pmem devices in list-devices-linux?


    I'll leave this to someone more knowledgeable :)

    4) Is it reasonable to consider a dedicated, shorter URL for serving Debian ISO images for UEFI HTTP booting, given the limitations of UEFI in handling HTTP redirects and to simplify the long URLs required for manual configuration ?


    Sounds reasonable but this may vary in usefulness from machine to machine: manufacturers find new and interesting ways to break installers in their firmware.

    Ideally, the Debian Installer would be accessible via the internet more
    often in the future, just like some SBC manufacturers have recently started to do. This would be possible to the extent that UEFI firmware support allows.

    Thanks.


    All the very best, as ever,

    Andy Cater
    ([email protected])

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