This is what I've used to build and upload Twigs using OSX 10.11.4
This is the AVR interface I'm using
brew tap PX4/homebrew-px4
brew update
brew install gcc-arm-none-eabi
git clone [email protected]:arirusso/twigs.git
cd twigs
git submodule init && git submodule update
OR
Latest stable source & dependencies package here
From the Twigs project directory
make -f makefile
brew install avrdude
Install AVRFuses from http://vonnieda.org/software/avrfuses
Connect the interface, red stripe facing in/towards the other side of the module
It's not necessary to power the module via Eurorack in order to upload. I have had both the AVR interface and Eurorack powering the module at the same time and it doesn't appear to cause any problems
From Twigs project directory
/usr/local/Cellar/avrdude/6.3/bin/avrdude -P usb -c usbasp -p ATmega88P -qq -B 10 -U flash:w:build/twigs/twigs.hex