I got Atmel Studio 7 generating code correctly after a brief struggle. It turns out there are some bugs in the current version, but you can work around them by adding some code to the Reset_Handler() method and manually setting the GPNVM bits rather than using the "Boot from" dropdown menu (which doesn't seem to work). That done, I have exerted control over the buttons, LEDs and card detect pins. Next is taking control of the HSMCI interface and crypto subsystems. The ability to actually interactively debug this stuff (rather than using tombstone debugging) is kind of amazing - almost worth having to run Windows for. Almost. :)

Real Life^tm is going to get in the way for the next few days, however. But I really want to get the firmware done by Halloween October. We'll see.

Oh, as before, the firmware will be open source, under GPL v2. There will be portions that remain under the original BSD license (since ASF is Atmel's code), but my stuff will be GPLed.