[ipxe-devel] Problem chainloading iPXE from some legacy Intel PXE

Michael Brown mbrown at fensystems.co.uk
Thu May 5 19:10:58 BST 2011

On Thursday 05 May 2011 18:03:35 Jedrzej Kalinowski wrote:
> >>  Any chance you could look into this issue. I can help debugging :)
> >
> > Try the attached patch with DEBUG=undionly and undionly.kpxe.  (It
> > will break
> > undionly.kkpxe.)
>  First, I've altered the patch a bit, because the pxeprefix_dump section
>  was added after the return statement so it wasn't accessed. I've moved
>  it 3 lines up.
>  Finally, I got this dump:
>  http://www.iem.pw.edu.pl/~kalinoj1/public/pxeprefix_dump.jpg

Thanks.  Sorry about the patch brokennesss.

This is properly strange.  The structure in .prefix appears to be intact, but 
the copy made in .data16 is empty by the time undibus_probe() executes.  I 
have no idea what could be causing this, especially since your binary is 
known-good on several other machines.

I would suggest that you try adding

  #include <undipreload.h>

  DBG_HD ( &preloaded_undi, sizeof ( preloaded_undi ) );

at various points in the code (starting with the top of main()) to find out 
when this structure gets zeroed out.


More information about the ipxe-devel mailing list