Adam,
I have finally (yahoo!) gotten ubifs to boot from NAND. I was copying both the zImage and the zImage_dtb over to my SD Card, that may have been the problem. But, I also think the User Guide may be missing some instructions. After I added the below two steps, the rest worked like a charm and the SOM boots very well.
Section 3.2.3
Load Linux from RAMDisk once to format and setup UBI partition in NAND
** NEW STEP** OMAP Logic # nand unlock
** NEW STEP** OMAP Logic # setenv loadzimage 'nand read $loadaddr kernel'
OMAP Logic # setenv ramdiskimage rootfs.cpio.uboot
OMAP Logic # setenv ramdisksize 100000
OMAP Logic # setenv mmcrambootz 'run ramargs; run common_bootargs; run
dump_bootargs; run loadzimage; run loadramdisk; bootz ${loadaddr}
${ramdiskaddr}'
OMAP Logic # run mmcrambootz
Thank you for the help, or at least for the listening/reading.
Elisabeth