HiVision Mininote

Hi!

We have a project. The netbook from HiVision comes pre-installed with linux and a not-so-crappy OS. We would like to enhance the gui and probably install additional apps. The system most probably uses U-boot.

I have the following questions:
1. Can I access the U-boot? I mean, can I get into U-boot and type commands without booting into the pre-installed OS? Once I reach the U-boot I can TFTP from a linux distro right?

2. The system does not have access to terminal. What do you think I can do to enable it? Or, is it possible?

3. Can I upgrade an embedded distro thru SD card?

Any help would be greatly appreciated.
Thanks in advance!