If you don't want to use this channel for console I/O, but just want to add an extra download command to redboot that you can add to the boot script, then you can do that using something like:
# include "redboot.h"
RedBoot_cmd("lvds_load",
"load over LVDS",
"[-w <timeout>]",
do_lvds_load
);
void
do_lvds_load(int argc, char *argv[])
{
// load the code
}
This will cause the function do_lvds_load() to run whenever the command lvds_load is issued.
If you look in packages\redboot\v2_0\src (in particular at main.c), you'll see examples of this.