I did the update in my AVIC-Z110bt, The GUI is awesome,if you follow the instructions everithing works fine. However the CNSD-OMM013, Optional Mexico Map (2009), didn't work anymore it said "Wrong Version", and for me is important because I live in México, I don't know if the 2010 version for Z110BT is going to work or I need the Avic-z120bt version of mexico maps. Any help is Welcome.

One question, in the future I have to download the updates for Z120BT or Z110BT?

You now have a 120 so all future updates/upgrades will be for the 120. You need to call Pioneer about your problem. I don't think anyone here can provide an answer.

Thanks for your help.

There is any way to change back from z120 to z110?

Not officially or that is known.