Build instructions for OS X don't work

Using the guide here: http://dev.ardupilot.com/wiki/building-the-code/building-px4-with-make-on-mac/, I’m unable to build using ‘make px4-v2’. First it complains about there being no config.mk file, and to run ‘make configure’. Doing so builds that file, and it’s unclear if it needs to be edited for Pixhawk or not. Running ‘make px4-v2’ a second time results in this:

$ make px4-v2 /bin/sh: line 0: cd: /Users/rmann/Projects/ArduPilot/px4/ardupilot/../PX4Firmware: No such file or directory ../mk/px4_targets.mk:12: *** ERROR: PX4_ROOT not set correctly - no nuttx-configs directory found. Stop.

This is all done from the ArduCopter 3.2.1 branch in the ArduCopter/ directory.

Is there a more current guide somewhere? Thanks!