I didn't find support for the SD card in the latest U-Boot, but I did find patches on the mailing list -- look for patches on Nov 21, 2010.I grabbed the 'stable' U-Boot from ftp -- 2010.12, and then applied the 3 patch files.The build went fine, so I am also going to try and fit the 'HUSH' shell, because I'd like the ability to run scripts (using 'Source') instead of hand-editing the U-boot environment variables.For some unknown reason, the sd card doesn't seem to work. So I guess I'll give up on this idea for now and go back to an older version without scripts but with reasonable mmc performance.