Note that Japanese FM frequencies (76-90MHz) differ from those in the US or Europe. An English manual won't change the hardware, so you may need an external "FM Band Expander" to receive local stations.
: An unofficial English manual for the AVIC-MRZ series is hosted on GitHub by btua . Pioneer Carrozzeria Avic-mrz09 English Manual UPD
: This involves entering a service menu (pressing the "Navigation" button while toggling track buttons) and replacing specific Japanese system files (like PF090JPJPN.lng ) with English versions on an SD card. Note that Japanese FM frequencies (76-90MHz) differ from