Wanting to further explore installations to nand, I decided to try the latest sheeva-with-linux kernal, and so created a new directory on my ESIA usb drive, "26342". From the Debian_squeeze directory, I copied to it root.tar.gz as my basic root filesystem and MANIFEST.cfg as a sample. I then got files from sheeva-with-linux.
I modified MANIFEST.cfg to reflect the proper filenames and md5 numbers.
Summary = sheeva-with-linux + Squeeze root ARM5 SheevaPlug Distribution
Description = This application consists of a Sheeva-with-linux kernel 220.127.116.11, & modules Debian Squeeze root file system (password: nosoup4u) and kernel modules from: http://sheeva.with-linux.com/sheeva/
rootfs.tar.gz = root.tar.gz
rootfs.tar.gz_checksum = 1C1A54095C8DF36627651D75A3FB0A04
uImage = uImage
uImage_checksum = cd49b2df58568e2104da0407a6a81017
modules.tar.gz = sheeva-18.104.22.168-Modules.tar.gz
modules.tar.gz_checksum = de10ee990b5698a2346fa15e42e95a5d
I then ran the ESIA/EPIA installer. Unfortunately, it died at 85% done, but I was hopeful that this was far enough along so that I could just add the uImage, so I did the following (I would have needed to do it anyway since I have a bad block in the uImage area which ESIA would have tried to overwrite):
fatls usb 0 /26342
fatload usb 0 0x800000 /26342/sheeva-22.214.171.124-uImage
nand erase clean 0x00100000 0x00400000
nand write.e 0x800000 0x100000 0x300000
This booted into a 126.96.36.199 debian system. I haven't played with it enough to confirm that it is stable and that nothing was omitted, but this appears to be a way to get the sheeva-with-linux kernels loaded and a ubifs file system. I updated password, timezone, /etc/hosts, and /etc/network/interfaces, and rebooted, and all appears to work.