UBoot and Changing The Default OS (no replies)

Hi, I have a Pogoplug V4-A1-01 and I would like it's change the default OS to Debian and update my uBoot version.
But I am not very literate in Linux, and I would like it if the steps used to resolve my issue were presented in layman terms. I would thankful l if anyone could help me.

Here is my:
---uBoot Version:1.1.4
---Linux Version: Linux-2.6.31.8