Kbdmap.c32
From Syslinux Wiki
kbdmap.c32 is a comboot module for Syslinux that loads a new
keyboard mapping on the fly.
The keymap format is the same as used in LILO.
Syntax
kbdmap.c32 path/to/map.ktl
Example
Here is a configuration example, specifying two keyboard maps in a menu:
LABEL be MENU LABEL Belgian azerty keyboard (be) KERNEL kbdmap.c32 APPEND maps/be.ktl LABEL us MENU LABEL US qwerty keyboard (us) KERNEL kbdmap.c32 APPEND maps/us.ktl