[syslinux] lpxelinux hangs under Intel Boot Agent 1.3.81 (2.1 build 089) on Dell Optiplex 990 BIOS A16

[Alexander Perlis]

Trying to PXE boot a Dell Optiplex 990 with BIOS A16, which has Intel 
Boot Agent 1.3.81 (2.1 build 089). It gets network and launches 
lpxelinux.0, I see the PXELINUX banner line, but there it hangs.

I tried both 6.03-pre18 and 5.10, same hanging behavior. If I instead 
use pxelinux.0 or gpxelinux.0, either 6.03-pre18 or 5.10 or 4.07, there 
are no problems. The problem seems isolated to lpxelinux.0, and isolated 
to this specific hardware/BIOS. We're otherwise PXE booting to 
lpxelinux.0 6.03-pre18 on a bunch of different machines without trouble.

I can update the BIOS to A18 and try again with possibly newer Intel 
Boot Agent code, if that report would help, but I only have this one 
machine of this type. Thus, before I upgrade to A18, in case any 
developers on this list want me to try anything with the current broken 
setup, if that will help isolate a problem in lpxelinux.0 (or a way for 
lpxelinux.0 to work around a problem in the Intel Boot Agent or Dell 
BIOS), I'll be glad to try some things and report back.

Alex