[gPXE] can we attempt chain-loading from the very first gpxe shell?

[Masroor Vettuparambil]

Hi all,

I tried to chain-load from the shell offered at the rom initialization
routine during BIOS POST. Then pxelinux.0 has been downloaded, but
execution got hung. 
My understanding is, rom initialization should not try this. Later after
completion of POST, when BIOS hands over execution to BEV routine, we
can try it. If that's the case, why gPXE offers shell from rom
initialization context?

Thanks,
Masroor