Fanoush - I went through the following steps and got bootmenu to do what it is supposed to do but got an error... "Boot from mmc13 failed... rebooting from flash"
sudo gainroot insmod <your filesystem modules> mount -t <yourfilesystemtype> /dev/mmcblkXpY /opt ls -la /opt
remove extra stuff? no <-- changed from original instructions in order to resolve boot issue
this brought up the bootmenu again (after a reboot) and again the D-pad let me navigate and the keyboard let me select and attempt to boot into mmc13
$ sudo gainroot # chroot /mnt/initfs cal-tool --set-root-device ask:mmc # reboot