[syslinux] Custom MBR

[Jeffrey Hutzelman]

--On Friday, December 12, 2008 11:22:29 AM -0800 YYZ <yyz01 at yahoo.com> 
wrote:

> Hi,
>
> Is it possible to always load syslinux from whichever partition it’s
> installed on, regardless of whether it’s active or not (and even if
> it’s a logical partition), just like grub?
>
> The MBR code that ships with syslinux (much like dos/windows default MBR)
> would only boot the active primary partition. It would be nice if you
> could provide a custom MBR such that one could set one byte in the MBR
> indicating which partition should be booted (0,1,2,3 for primary/extended
> and 4,5,6,… for logical) and install it in the sector 0. Thereafter,
> upon system restart, instead of searching for active partitions, the MBR
> could would just load the correct boot sector and execute it.

So in other words, the MBR would boot a partition designated by data stored 
on the disk, but instead of using the standard mechanism for this, you'd 
have it use some new, nonstandard mechanism that nothing else supports.

Why?