The machid (arcNumber) for the dreamplug is 3550

And the reason these variables are set is to override the wrong number u-boot has been told to use.
GNOME3 - don't get me started...anyway that's your rant

, apparently they are making changes so that it will work without hardware support.
It's all going to be offloaded from the GPU to the CPU, good luck running that responsively on a plug.
Kudos to yourself, you keep good company, Linus also switched to Xfce from GNOME.