[syslinux] "--once" support / ADV

[Gene Cumm]

On Sat, Apr 5, 2014 at 7:46 PM, Garth Hitchens <ghitchens at me.com> wrote:
> I wonder if anyone can help me understand syslinux --once support - it appears supported since 4.00 (it's in the changlog), but the syslinux (4.07) command gives the message "At least one specified option not yet implemented for this installer.".   anyone using boot-once with syslinux?

Which installer (linux/syslinux, extlinux/extlinux, mtools/syslinux,
dos/syslinux.com, win32/syslinux.exe win64/syslinux64.exe)?  What
exact command line?

> Alternate question:  since this is for an embedded device I would prefer not to have to install the syslinux installer on the device -- is there an alternate way to write directly to the ADV (like a known offset into a file or partition or boot record) that would allow me to enable boot-once?  I like syslinux but I'm trying to get firmware upgrades working on an embedded device and need boot-once functionality.  Am I out of luck?

In short, you'll need an installer binary OR write your own app to do
it (likely reusing the code).  Accessing the ADV would essentially
require the Syslinux code to do it.  There is no fixed offset as it's
the last portion of a file (ldlinux.sys) that varies in length based
on version and even between build machines.

-- 
-Gene