[syslinux] Pre-PXE loader

[Roger Binns]

H. Peter Anvin wrote:
> You should be able to use gPXE as the ROM-level loader with static 
> configuration to bootstrap PXELINUX.

I can't see any static configuration in the gpxe rom-o-matic download page.

What I have so far:

Device boots and gets DHCP NAT address 10.0.2.15 and a gateway of NAT
router.  NAT also provides next-server of router and gpxe filename.
Device loads gpxe, says hit ctrl-b for cmdline and if nothing is pressed
goes into loop of rebooting itself as you would expect.

If I get a commandline, I can't figure out what to tell it next (the
commands are not documented other than a few words *).  The various
config/set/show commands all say "No non-volatile option storage
available".  I managed to figure out "ifopen net0" and "dhcp net0".  If
I tell it to get the 2nd pxe image I really want with "imgfetch
tftp://192.168.1.25/pxelinux.0" then it claims the file doesn't exist.
Using sniffing I worked out that is because it is trying to download
from the NAT router not the IP address I gave it!  However giving an
http URL did get it from the correct machine, but imgexec gives error
0x3d008001 (also not in Google).  From the source code it looks like the
config command is some sort of interactive UI.

Basically what I am hoping for is some sort of image that can be loaded
via almost any means (pxe/cd/grub etc) which then provides an
interactive way for me to specify what to actually boot
overriding/providing parameters as necessary (eg another pxe server
address and filename).  GPXE doesn't not appear to be it.

Roger

* Unbelievably there are no Google hits for gpxe command line
documentation either.  For example try finding a page containing
imgfetch, imgload and imgexec.