I have also tried the http://people.debian.org/~tbm/u-boot/2012.04.01-2/sheevaplug/u-boot.kwb
uboot and had exactly the same result. I guess there is some error in the patches as applied there. You can revert to pingtoo 3.4.27 and that should get you back to where you were before. I have looked at the patches from here http://people.debian.org/~tbm/u-boot/2012.04.01-2/u-boot_2012.04.01-2.debian.tar.gz
and will attempt to patch the latest denx code and rebuild. Did you try and contact tbm?