Thank you sir.. I was missing the documentation on the 2015 update, and though I suspected this was the case, had nothing in black and white... Greatly appreciated! A
Any idea how to manage installing 4.6 or 5.1 firmware on a device already at v.6.0.. the instructions call it out, but no release of a 6.1 or <, and no mention of how to tackle out of order update install.. sure would have been nice of pioneer to either include the patch, or at least perform a check and warn during the upgrade process.
Don't suppose there are any known tricks to either make the unit think it's on a prior revision, or to alter the 5.1 update files (manifest?) to identify as 6.1, etc.. you get the idea. Or does it even matter? Pretty sloppy code mgmt on the part of Pioneer.. not sure why i'd expect any different though.
I've heard of people going back to a previous version but I don't know how they did it. Sounds like you have a backup of USER already prior to installing 6.0. Before you try anything, use a different SD to backup the current USER. Just to be safe.
So you are saying that your "virgin" z140 never had the 4.6 or 5.1 patches to support Lightning? And now you want to retro-install one. Those idiots at Pioneer - there's no way to actually follow those instructions in Chapter 6. If you had already installed 5.1, the iPod Settings would already be there. And if it's not there, there's no way to install it after the fact. 
Well, here's an idea that might work. Your unit has two PRG folders (PRG0 & PRG1). Since it was "virgin", they originally should have copies of the same software. When you installed 6.0, one of them got overwritten. The way to tell which is whether the file USER\PRG.FLG exists. If it does, then PRG1 is the "active" firmware. Otherwise, PRG0 is. So you might be able to delete or create this file to revert back to the other firmware (v4.0). After making the change, I'd do a hard restart by disconnecting the battery. If it then boots-up OK, you should be back to the old version. You can check in the settings system information. Then try to install the v4.6 patch. If all looks good, try installing 6.0 again.