Ergodox left side not working

[Squeaky Wheel]

I assembled the Ergodox, flashed the eep ande hex files and connected the sides with the cable...and I'm not picking anything up on the left side of the keyboard. Has anyone else had experience with this? The right side works fine on both Mac and Windows.

[handystack]

I had this problem when I first assembled my ergodox.  It turned out that I had neglected to jumper the proper connections on the TRRS jacks.  Here are the steps that solved my issue:
https://www.massdrop.com/ext/ergodox/assembly#step-5