Hacking a Car

This post details my adventures with installing CarPlay on a 2017 Mazda Cx-9.

The setup

Buying the parts was fairly easy. On the mazda3revolution forums, there's a parts list depending on the car's model/region. In addition to the factory parts, I also bought tools needed to obtain serial access on the car's CMU head unit. These parts are only required if you want to install tweaks that can remove disclaimers, enable touchscreen access, reduce delays, and more. The parts for serial access can be found on mazdatweaks.com.

Updating the Firmware

Before I could install the parts, I had to update the Mazda CMU firmware to v700.00.335. So took off the trim and unbolted the CMU from the harness. I had researched tweaks for the Mazda and realized that I would have to install a small patch during the update process to maintain root access, something needed for tweaks. This process is done through the serial ports. To access the serial ports, you connect a transmit pin and a receiver pin to the back on the unit. As much as I tried, I failed to create a stable connection between the pins and my laptop.

So as a last resort, I opened up the CMU and soldered the pins directly onto the circuit board. After finally fiddling with the baud rate (the information transfer rate), I could see the logs scrolling on my terminal screen.

After that installing the software was a breeze. After the software was installed, I was able to run the commands for AIOMazdaTweaks detailed in this post here.

Installing the Hardware

Installing the hardware took a while. The main challenge was running the new data cable through the center console. I failed to take pictures of this, so instead I'm going to link the youtube video I followed.

Final Product

This project presented many unique challenges, and I am glad I got to experience them in a hands-on manner. Carplay is perfect, and the various AIOMazdaTweaks removed many annoyances I had with the Mazda UI. Overall, I'm pleased with the final result and hope this will inspire many projects in the future.