Just recently I bought a wireless CarPlay/HDMI adapter because my car doesn't support wireless Android Auto/CarPlay and also it seemed like a neat idea to be able to use the screen to play Switch games and stuff (charging an EV can get a bit boring on road trips).

I happened to buy this one, an Atoto AD1 for the simple reason that it is the cheapest device of this type sold on Amazon that I could get reasonably quickly. It also has a USB C port instead of a yucky integrated USB cable.

Unfortunately, it doesn't support Android Auto*. Officially. Fortunately, looking at reviews for other devices like this, I noticed that they all "coincidentally" happen to have identical looking menus for selecting between HDMI and wireless projection. I also noticed that Ottocast sold a device with several variants: HDMI only, HDMI + CarPlay only, and HDMI + CarPlay/Android Auto. And guess what? Ottocast hosts the firmware online to manually update your device, so I found the firmware for that one that supports all three. I went with the firmware for "3421". My version number was "25043220.3437.2", which seemed close enough to "3411_AUTO_20250423.img" compared to "3411_AUTO_20250811.img".

After a brief disassembly by popping the clips on my Atoto, it revealed a reset button for flashing. On the Ottocast, there would have been a hole. Funnily enough, Atoto included a pin despite not having a hole for the reset button. At any rate, following the firmware flashing instructions for the Ottocast went perfectly and successfully flashed the device.

Now I have a little wireless projection thingy that support Android Auto. Yippee! I will say, it's definitely more compressed and there's a slight lag compared to a direct USB connection, but it works and that's all I really care about.