NOTE for Mazda RX-8

The factory head unit's firmware revision must be between 9.55 and 9.99. The unit will not work on earlier firmware revisions or with 10.01. To find out which revision your Mazda RX-8 has, make sure the radio (FM) is turned on, then press and hold "TEXT." Then, also press and hold "1" at the same time for a few more seconds. The LCD should then report your firmware version.