I have my Z2 hooked up with the 2 wire bypass. I downloaded the iso file & burnt it to a disc as an image using nero. when I put the update disc into the Z2 it tells me that the inserted update disc is already updated? I hit the reset button & still get the parking brake crap! help!

You do not have the 2 wire bypass done correctly. Be sure that you moved the 'mute' (or other wire) to the correct location in connector 2. Be sure that the wire you moved is completely seated in the connector and making good contact. Be sure that the wire is connected to a solid ground.

I can assure you that I do have the 2 wire bypass installed correctly. I have double checked this using my volt meter. This is a june 2007 model. I just took it out of the box & hooked it up. The Z2 says the update is already installed? Is there any way to overwrite the update?

New ones already have the update, you can't update it again. It's the same thing.

Your 2nd wire is improperly grounded.

OK, I checked the 2 wire grounds & they are good. I pulled the HD out & put it back in. Turned the unit on & hit the reset button. I not plays the DVD's while in motion but I still get the parking brake warning. Once I press ok, the didplay comes back on though. Is there a way to get rid of the warning all together? Also, is there a way to control what is displayed on your headrest monitors that are hooked up to your video out? I am wanting the headrests to display the DVD only, & not cut off when I go to the map screen? Is this possibe?

If you get the parking brake warning, then your second ground wire is not correct. See my post above.

There is a setting for the rear monitor to mirror the front or DVD only.