Yeah, I just discovered the same thing. I went all
ranty about it. I switched to Gnome, but Gnome3 has it's own issues. Redhat has the same problem since they are using Gnome3 also. Irritating as all hell.
Could you post instructions on doing the tftpboot under Ubuntu? I'd appreciate it. Why are you looking for u-boot images anyway? Isn't your u-boot working?