Short update: Setting address and erasing pages work now, after I fixed a “typo” in my address parsing code. The rest should be straight forward but I have not so much time…
Tip for those who want to debug USB on Linux: wireshark works great for USB sniffing, but you will need a recent version. For Ubuntu 10.04 you can find updated packages for wireshark and libpcap0.8 in my PPA https://launchpad.net/~tormodvolden/+archive/ppa. It seems like you have to launch it with “gksu wireshark” to be able to read the USB streams.
Also, for working on the DFU without sudo, make a /etc/udev/rules.d/45-dsonano.rules file with this:
ACTION=="add", SUBSYSTEM=="usb", ATTRS{idVendor}=="0483", ATTRS{idProduct}=="df11", MODE="660", GROUP="plugdev"