I wonder why the shipped U-Boot does not support booting from NAND.
(UBIFS support disappeared as well from U-Boot).
On a BBxM revB I installed MLO and U-Boot on NAND, but got the usual error (60... 60... 60...) at boot when the microSD card is absent; this means that MLO only wants the U-Boot on the card.
Latest ArchLinuxArm's mtd-utils does not show the 256Mb MTD NAND; I also tried to load the relevant mtd kernel modules, with no result. It seems that ArchLinuxARMv7 dropped support for it.