Ground lug for Gen V Macintosh HU Hack

[legalis]

Ok, so my car's HU is in pieces and I have successfully installed my cable into the spare port in the green plug.....then I look for the ground lug as specified in the instructions. There is nothing that looks like it on the back of my Headunit. I have attached pics ( as best i could get), but I cant for the life of me find where to screw the wire to get grounding. I know it has to have a ground point, and a lot of GEN V owners have done this mod

Any help would be great.

UPDATE
I have a suspicion that I have found the ground wire connector (its the silver metal L bit in Pic 1 that can be unscrewed), but it has no ground wire coming off it. Is this normal for a factory HU not to be grounded?

[satogixxer]

I seem to recall my unit had a ground wire connected to or near the metal piece in your pic. I did examine it when I was looking to connect the nav hack cable (cd-rom audio cable) to ground. It was hard to get to so I ended up connecting my nav hack cable to the chassis since it all should be grounded. This was a long time ago now, and I've never had any issues.

If your unit is not grounded that is a bit odd and could be a problem - have you looked around for a loose ground wire behind the unit?

[legalis]

Cheers for your help. I decided to test it by wiring it to the HU bracket. Works fine. Obviously in the MY14's they have grounded the HU via one of the plugs rather than the ground lug.