using initrd preseed.cfg during netboot

[Steve Feehan <sfeehan@sbb.uvm.edu>]

I have been working on preseeding during network booting. I got a
network preseed file to work, but I'm having trouble putting the
preseed.cfg file in the initrd.

First, I know this is probably not the correct way to modify the initrd, 
but here is what I did:

Uncompress the initrd:

  gunzip initrd.gz

Mount on a loopback device:

  mount -o loop=/dev/loop0 initrd /mnt

Copy the preseed file into the initrd file system:

  cp preseed.cfg /mnt/preseed.cfg

Unmount:

  umount /mnt

Compress the initrd:

  gzip initrd

When I boot with this initrd I can drop to a shell and see that
/preseed.cfg is there. But the installer won't use the values in
the preseed file. I've tried with and without passing the kernel 
parameter:

   preseed/file=/preseed.cfg

But in either case, the preseed values are not used.

Am I missing something obvious? Does the netboot initrd not support
preseed files inside the initrd? Do I need to build my own customized
netboot images? If there is documentation on this, please point me in
the right direction. And if I didn't explain the problem clearly enough,
please let me know and I'll try and clarify.

Thanks for your time!

-- 
Steve Feehan