Needs migen and ISE.
make
# and then look at/use flash.sh or make flash
# or use fxload and xc3sprog:
/sbin/fxload -t fx2 -I /opt/Xilinx/14.7/ISE_DS/ISE/bin/lin64/xusb_xp2.hex -D /dev/bus/usb/001/*`cat /sys/bus/usb/devices/1-3/devnum` && sleep 10 && \
xc3sprog -c xpc -m /opt/Xilinx/14.7/ISE_DS/ISE/xbr/data -v build/urukul.jed:w
# look for "Verify: Success"