Bug#942028: Bootloader file located in same directory as ldlinux.c32

[john doe <johndoe65534@mail.com>]

Package: debian-installer-10-netboot-amd64
Version: 20190702+deb10u1

Following the recommendation of (1) and (2) the pxelinux.0 (bootloader)
file should be in the same directory as the ldlinux.c32 library:

"On the TFTP server, create the directory "/tftpboot", and copy
"pxelinux.0" (from the Syslinux distribution) and any kernel or initrd
images that you want to boot.
[5.00+] Also copy "ldlinux.c32" from the Syslinux distribution to the
"/tftpboot" directory on the TFTP server."

Sadly, Debian does not follows those guidelines and creates an issue if
you want to install Debian 10 (Buster) using PXE boot with the local
tftp server of Qemu for Windows.

The issue only manifest itself on Windows, steps to reproduce:

- Copy the text directory from this very package into the root directory
of Qemu's local tftp server
- For sake of completeness, recreate the symlinks Windows way:

    del /q ldlinux.c32
    del /q pxelinux.0
    rmdir /q /S pxelinux.cfg

    mklink ldlinux.c32 debian-installer\amd64\boot-screens/ldlinux.c32
    mklink pxelinux.0 debian-installer\amd64\pxelinux.0
    mklink /D pxelinux.cfg debian-installer\amd64\pxelinux.cfg

- Start Qemu with the following command:

    qemu-system-x86_64  -boot n -net user,tftp=<PATH>,bootfile=pxelinux.0

- Error message

    "Failed to load ldlinux.c32
    Boot failed: press a key to retry, or wait for reset..."

- Workaround:

    Given that ldlinux.c32 is in 'debian-installer/amd64/boot-screens'
and not in the root directory of the tftp server the only workaround is
to copy ldlinux.c32 in the root directory of the tftp server by doing:

    del /q ldlinux.c32
    echo F|xcopy /S /Q /Y /F debian-installer\amd64\boot-screens\ldlinux.c32


If ldlinux.c32 is in the same directory as pxelinux.0 it works.


See also (3) and (4) for more context.
Note that all commands are to be executed in the tftp root directory.


1)  https://wiki.syslinux.org/wiki/index.php?title=PXELINUX
2)  https://www.syslinux.org/archives/2019-September/026536.html
3)  https://lists.debian.org/debian-boot/2019/09/msg00152.html
4)  https://lists.debian.org/debian-user/2019/09/msg00817.html

--
John Doe