I am not sure what shairport-sync is. All I did was install the convenience installer:
curl https://get.pimoroni.com/airdac | bash
In any case, I checked and shairport-sync is already in the i2c user group:
$ groups shairport-sync
shairport-sync : shairport-sync audio i2c
I don't see how your setup would be different than mine. I simply installed Jessie (2017-04-10-raspbian-jessie) from scratch, ran the convenience installer, then added the steps you outlined above. I am also running speakerphat-server.py in the background with the
I've tried starting and stopping, connecting and reconnecting several times but the result is always the same. I can get audio via AirPlay but no LEDs light up unless it is a local file/stream on the pi zero.
I am using a Pi Zero Wireless if that makes a difference.
Incidentally, your instructions above about making a change to the 60-i2c.rules, has the "GROUP" set to "i2C" with an uppercase 'C'. Is that right? On my pi, when I type "groups", I see "i2c" with a lowercase 'c'. In any case, I changed that line to use the lowercase "i2", rebooted, and reran the python server script "speakerphat-server.py" in the background but no change.