PXE booting a custom Debian installer hangs at "your installation media couldn't be mounted"

[Eike Sauer <eike.sauer@web.de>]

Hello,

we're trying to install our system using a custom made installer ISO (based on the Debian installer) via PXE. 
Well, I wouldn't be here if it would work out. :)

We've put quite some work in the installer, which is made using simple-cdd, so we'd want to use it.
It does unattended installations from USB thumb drive all fine.

Now we want to boot it over PXE to do the installations. We've tried different methods 
(PXE using HTTP and/or TFTP, Sanboot with a virtual iSCSI disc, ...), and they do boot the ISO 
- we can see our custom grub menu, so we know it's the right data -, but then, the installer 
wants to remount its source device and fails ("your installation media couldn't be mounted").

I have read PXE reconfigures the drive interrupt (INT 13) and that this is reverted by the newly
loaded kernel. So  I guess the ISO data (~3 GB) already transferred is "lost in translation"?

But if so, retransferring it would be ok. We took a look at the system hanging at the error message. 
Maybe we could pass enough information via grub to the kernel? In our test system (VM to VM), 
to our surprise we didn't even find any network device except the loopback adapter at this phase. 
Despite the installer's network configuration would come after the mounting step, so it didn't yet 
happen in our case, I would at least expect some network device I could work on?

So... 
* Is installing with a custom Debian installer via PXE possible?
* Can we use the data transferred in the beginning (by somehow mounting it)?
* If not, can we retransfer the data and mount it (by NFS maybe)?
* Would you expect a working network device at the installer's remounting phase?
* Help?!? :)

Ciao,
  Eike

PS: Is there a better mailing list for this? I figure debian-boot is for the development of Debian itself only?