If anyone ever wanted to erase their music partition on the AVIC-Z1 and rerecord here is the method to do so. This is the query I sent to Pioneer and their response below.
Inquiry: I have an AVIC-Z1; and want to erase all the music content on the HD Partition at once, is there a way to do so?
Thank you for contacting Pioneer Electronics, Inc.
By doing this reset it erase everything you have saved on the unit.
1 Turn the ignition switch off.
2 Press the RESET button.
3 Start the engine.
After a little time, the start-up screen comes
on for a few seconds.
4 Touch and hold the MAP button while the
start-up screen is displayed. The Clear memory screen appears.
5 Touch [Clear user information from hard
disk]. This reset operation clears all music data
recorded in the music library. Note that the
cleared data cannot be restored.
6 Touch [Yes].
The user area in the hard disk drive is initialized.
After that, the navigation system restarts.
