[syslinux] Current pxelinux always unloads undi driver

[Pedro Koschi]

Good day,

I have the problem to pass  the “loaded“ undi driver to the next bootloader.

In current pxelinux

“lernel memdisk keeppxe harddisk raw initrd::parh_to_img“

always unloads undi before memdisk (or other kernel) takes control.

After many tries I found that the keeppxe feature is broken starting from
version 6.03 pre 9.
I tried to find the reason by comparing sources 6.03 pre 8 / 6.03 pre 9 but
can't see any keeppxe related  (obvious) changes.  Unfortunately i'm not
able to offer a fix but I would be happy to see it fixed.  Many thanks!