The latest revisions of the FreedomBox unstable images makes it significantly easier to get the image onto your DreamPlug: you don't technically need a JTAG any more, if you don't mind opening it up. The latest image is built to boot the system when DDed to a 2GB (or larger) microSD card.
Accept the fact that you are about to void the DreamPlug's 30 day warranty.
- Pop out the card and plug it into your computer/microSD adapter.
- Fiddle with /etc/fstab as necessary.
- Wait around an hour, depending on your card's write speed.
Pop the card back into your DreamPlug.
- Bask in the glory of your sheer awesomeness.
You can also Boot from an external SD card.