U-boot supports network console. Add this to the board config file:

#define CONFIG_NETCONSOLE 1

Rebuild and reflash your image.
Then tell uboot where your desktop is and redirect the console.

uboot> set ncip 192.168.1.4
uboot> set stdin nc; set stdout nc

Start nc (network cat) on your desktop.

jonsmirl@terra:/home/apps/u-boot$ nc -u -l -p 6666 < /dev/null &
[1] 5444
jonsmirl@terra:/home/apps/u-boot$ nc -u 192.168.1.11 6666

And now you're connected. Next I have to figure out how to make this the boot default.