[syslinux] help with porting patch from 1.62 to 1.75

[H. Peter Anvin]

Mathias Koerber wrote:
> Hello List,
> 
> I have below a patch (against Syslinux-1.62), which adds
> a pseudo-kernel 'swap' which swaps device numbers of
> the boot device and the first harddisk. It was made
> for a system equipped with a DiskOnChip (www.msys.com)
> device which 'steals' the device# of teh first harddisk,
> This patch is used to enable the syslinux on the DoC
> to continue booting from the harddisk as if the DoC
> isn´t present.
> 

It would make more sense just to load the boot sector from the secondary 
drive and call it with DL=81h.  SYSLINUX basically has all that code 
already, although I can't remember for sure if it's enabled in the 
SYSLINUX module.  Try entering "localboot 0x81" ISOLINUX-style; I 
believe it should work in 1.75 SYSLINUX; if not, let me know.

Note that some other boot loaders/MBRs might have a problem with booting 
from a non-80h hard drive.  SYSLINUX won't have any trouble.

	-hpa