[syslinux] Howto create hd image with bootable (Free)DOS system

[Dominik Fischer]

Hello,

I have to update the BIOS of several hundreds of geographically
distributed PCs.
Since we are using PXELINUX for years to install the OS (Linux) on this
PCs PXELINUX is my
first choice for doing this job.

The vendor of this PCs provides a bootable ISO image for the update.
Because of the size of the
firmware it is not possible to use a FD image (not even 2.88MB).  But in
the documentation
of PXELINUX there's a hint that bootable hd images are also supported by
PXELINUX.

I've no success on creating such an image so far. Does anyone have
successfull created such an
image and can give me a short howto for this?

Kind regards,
Dominik