Syslinux - Dec 2010 - Enable debug messages for gpxelinux.0

All,
For several days, I've been trying to debug an issue booting a Windows 7
machine over iscsi (utilizing gpxelinux.0 and sanboot.c32).
?
??? - I can get it to function OK utilizing plain gPXE (so I know my iscsi
config is OK and also the iscsi drive is OK).
??? - When utilizing gpxelinux, the system shows that the iscsi drive is
mounting and trying to boot. However, at that point the system hangs.
?
?
To troubleshoot this issue, I'm trying to enable the debugging messages in
int13.c 9 (which is called by iscsiboot.c). I'm not having any luck
(I've already recompiled gpxelinux.0 enabling the gpxe gdb debug options per
the gpxe website). Can someone point me in the right direction on how to get
gpxelinux.0 debug information?

Good day David,

Change the Makefile at syslinux/gpxe/Makefile:

  src/bin/undionly.kkpxe: pxelinux.gpxe ../core/pxelinux.0
          $(MAKE) -C src bin/undionly.kkpxe NO_WERROR=1 \
          DEBUG=int13
EMBEDDED_IMAGE=../pxelinux.gpxe,../../core/pxelinux.0

- Shao Miller