Syslinux - Aug 2016 - Install syslinux on GPT drive with Windows

I'm trying to make a drive that can boot with both UEFI and BIOS. I've
built the drive successfully on my Linux machine, but can't get the drive
to build with my Windows machine. The only step that's different right now,
is that I use `extlinux --install /media/drive` to install with Linux, and
`syslinux.exe --install d:` to install with Windows. In fact, I can prepare
a drive with Windows, try and fail to boot, then stick it in my Linux
machine and run `extlinux --install /media/drive` and then it will boot.
Note that this is a USB flash drive that I've formatted with diskpart as a
gpt, enabled the gpt legacy boot flag, and installed gptmbr.bin to the
first 440 bytes of the disk. The only thing that I can't figure out is why
extlinux --install works but syslinux --install doesn't. Does anyone know
why this might be?

On Mon, Aug 8, 2016 at 7:09 PM, Erik Sandberg via Syslinux
<syslinux at zytor.com> wrote:
> I'm trying to make a drive that can boot with both UEFI and BIOS.
I've
> built the drive successfully on my Linux machine, but can't get the
drive
> to build with my Windows machine. The only step that's different right
now,
> is that I use `extlinux --install /media/drive` to install with Linux, and
> `syslinux.exe --install d:` to install with Windows. In fact, I can prepare
Version number and build source of each might be handy.
> a drive with Windows, try and fail to boot, then stick it in my Linux
How does it fail?
> machine and run `extlinux --install /media/drive` and then it will boot.
> Note that this is a USB flash drive that I've formatted with diskpart
as a
> gpt, enabled the gpt legacy boot flag, and installed gptmbr.bin to the
> first 440 bytes of the disk. The only thing that I can't figure out is
why
> extlinux --install works but syslinux --install doesn't. Does anyone
know
> why this might be?
The most likely answers are Windows AV software, a build interaction, or a bug.

Any chance of getting copies of the VBR, the original, after
syslinux.exe then after extlinux?  If the first two are identical, I'd
look at AV software first.

-- 
-Gene

Well... Nevermind lol

I never got anything to boot yesterday without using extlinux but today I
followed the steps that I had written for myself yesterday and now it's
working with syslinux.exe and never touching my Linux machine. Go figure.
Thanks for the help anyway.