what exactly are these files?

Hello all, as this is my first post I hope it is in the correct list. I'm following the Freedombox project and have a Dreamplug, jtag combo. I'm after more detail such as a schematic or some explanations or clarifications.

As I've tried to follow the boot sequence of the DP I keep wondering what exactly the definitions of the files that it loads, specifically uinitrd and uImage they are defined in the boot sequence as initrd and kernel.

Is that really they? Is not one of them the ram disk and one the loader? It would help to determine what is what.

Also, can the 4G SD internal card be replaced with a 16 G internal SD card? I've written the Global people about it but their positive response is low (0 % so far).

Also, if I read the boot sequence right the first drives (internal SD card should be the sda drives, is this correct?

When I try and run the copy2dream, it fails on the format saying the drives are in use or something.

Thanks