[syslinux] PXE boot img for both BIOS and EFI

[Gene Cumm]

On Tue, Dec 18, 2018 at 5:44 PM Ady Ady via Syslinux <syslinux at zytor.com> wrote:
> On Tue, Dec 18, 2018 at 4:02 PM Joakim Tjernlund <Joakim.Tjernlund at infinera.com> wrote:

> > What about booting syslinx from GRUB2 UEFI ?
> > that is instead of PXE boot from BIOS I want grub to start some syslinux binary that
> > continues behaves like PXE boot.
> > I want to automatise the PXE boot so I can initiate one by rebooting into GRUB go from there
> >
> >  Jocke
>
> @Jocke,
>
> I could be wrong but... You seem to be missing the fact that, in
> addition to booting a local device (e.g. HDD)  syslinux.efi can be used
> for network booting in UEFI mode, in a similar way as {l,}pxelinux.0 is
> used for BIOS (although with much less features / capabilities, ATM).
>
> FWIW, the Syslinux wiki includes this information.

If you're already loading GRUB2 UEFI via PXE, loading syslinux.efi
should be trivial if GRUB2 UEFI can load plain UEFI images.  I think
it can but I can't be certain.

If you want to load GRUB2 UEFI from an HDD ESP then chainload to
syslinux.efi over PXE, this would depend on the above PLUS making the
appropriate UEFI calls to configure networking (load base, select NIC
and run DHCP) then load a UEFI image and execute it.  Unlike BIOS
which requires something like iPXE/gPXE/EtherBoot, I have a feeling
this is just a matter of a bunch of API calls.  Worst case if GRUB2
UEFI hasn't been programmed for such or your system can do it, you do
something similar to BIOS and load iPXE which still has the dependency
of loading a plain UEFI image.

-- 
-Gene