[syslinux] Returning to syslinux bootloader

[H. Peter Anvin]

Dag Wieers wrote:
> Hi,
> 
> I was wondering whether it is technically possible to go back from eg.
> DOS or Linux directly to the bootloader (instead of rebooting the
> hardware).
> 
> We currently have 2 images (one DOS and one Linux) that need to be
> started before loading a system. They do things like disable PXE on NICs
> (using an Intel DOS tool), verify the correctness of the network
> patchings and validate if the hardware was configured according to
> corporate standards (usage of PCI slots, hardware revisions and firmware).
> 
> But rebooting the hardware on certain devices takes a long time, if we
> could go back to the bootloader it could be useful. Even when the
> hardware may not be properly reset.
> 
> I noticed that HDT can exit and return to the bootloader without a
> reboot, the same could be useful for memtest and some other tools that
> are not com32 modules.
> 

There are major differences, though.  When HDT runs, the hardware is not
reprogrammed and the bootloader is kept in memory.  Although it would be
theoretically possible to restore the pre-OS state, noone has actually
built that.

	-hp

-- 
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel.  I don't speak on their behalf.