Ubuntu + C4, Partition Disappears


I have a Beagleboard rev C4, I was running Angstrom from another SD
card but wanted Ubuntu. I went with the preinstalled image for the
OMAP3 (http://cdimage.ubuntu.com/ubuntu-netbook/ports/releases/
maverick/release/) following the instructions here
https://wiki.ubuntu.com/ARM/OMAPMaverickInstall . When I dd the image
to my card, the ext2 partition disappears. When I go to boot the
board, it starts to boot, the video goes funky, then I just get a Tux
at the top left corner of the screen.

Unfortunately, the serial port on my board doesn't seem to be working
anymore (it was working fine for the first month or so, the cable has
been tested and seems to work... this is another issue I've been
looking into) so I can't see what kind of message I'm getting on
boot. The NAND is not bootable, so I know it is trying to boot from
the SD card. I haven't been able to find similar problems online but
if anyone has an idea of what's going on, please let me know.