Mazda 6 (2016) touch input not working — input_source_service channel 0x02

[Hawkweber]

Setup:

Vehicle: 2016 Mazda 6 (GJ)
Head unit firmware: 74.00.311 NA N
CMU root method: mzd-connect-1-root
Device: Raspberry Pi Zero 2 W
Build: 20260623_045946
Phone: Google Pixel 9a

Configuration:

MITM: enabled
remove_tap_restriction: enabled
Certs: from Discord

Issue:

Touch input does not work in Android Auto despite remove_tap_restriction being enabled. The log shows the following during service discovery:

mitm/HU: input_source_service channel is: 0x02

MITM is confirmed working — DPI override is successful per the log. TLS handshake completes on both MD and HU sides. The remove_tap_restriction option appears to have no effect on the Mazda 6 head unit.

Vehicle identity from log:

vehicle=veh_acb9796e48eb (Mazda / 3478fbe3b948face392a476a425e3c85)
profile_enabled=false

Additional context:

Touch is enabled on the CMU via mzd-connect-1-root and works in the native Mazda Connect interface while driving. However touch does not work in Android Auto. Community research confirms this is a known limitation of the Mazda CMU firmware at the protocol level — the HU reports 0x02 (rotary/knob) as the input source to Android Auto regardless of CMU touch settings.
Is there a way to patch the input source value via MITM or SDR profile to report touch capability to the phone? Happy to provide additional logs if needed.

[manio]

Hi
I remember a similar discussion. From what I recall, on Mazda the HU doesn't pass touch input through the protocol at all (just like you described). And if I remember correctly (though I could be wrong), the only option was to use CarPlay.

There are also some dongles that somehow wrap Android Auto into the CarPlay protocol to work around this limitation and enable touch controls.

Simply adding it to SDR probably won't help. As far as I remember, someone on Discord actually tried doing that already.

If it's really important to you, I can try to dig up the old discussion, but since you're on Discord, I'm pretty sure this topic has come up there before.

[Hawkweber]

manio - thank you for responding. I am on Discord, but the search feature is rather limited as far as I am concerned and finding the right query string, and then reading through the conversations it rough.

So, even if an SDR is done to intercept the 0x02 input_service_channel to 0x03, it won't work because the Mazda isn't sending touch commands at all?

[Hawkweber]

Manio - Update: Tested CarPlay with an iPhone on the same head unit. Touch works both parked and in motion, confirming the CMU touch patch is functioning correctly at the hardware level. The touch input pipeline to the screen is intact — the limitation is purely in how the Mazda CMU declares its input capabilities to Android Auto via the SDR.

[manio]

manio - thank you for responding. I am on Discord, but the search feature is rather limited as far as I am concerned and finding the right query string, and then reading through the conversations it rough.

I just typed mazda and have a plenty of. What is your nick?

Manio - Update: Tested CarPlay with an iPhone on the same head unit. Touch works both parked and in motion, confirming the CMU touch patch is functioning correctly at the hardware level. The touch input pipeline to the screen is intact — the limitation is purely in how the Mazda CMU declares its input capabilities to Android Auto via the SDR.

I doubt it would help. HU should also handle events. Even if you add this by hand it would probably break (not respond) when phone will try to open events channel/send events...

[Snirpo]

If touch doesn't work with a wired connection (which I'm pretty sure of is the case with these cars), it's extremely unlikely it's going to work by hacking into the AA protocol.

[Hawkweber]

I just typed mazda and have a plenty of. What is your nick?

If asking about my name on Discord, it's Mannyweber. Typing in Mazda gives 51 results, and after taking out the ones that came over by my github queries, there are very few that refer to touch screen, other than how to remove the touch disable block when moving for the Mazda Connect.

There is some discussion about this with Tehan, DeadKnight, and you back in 4/2025, but the post titles don't indicate "Mazda" per se, or "touch", and definitely not both, so I had to do a lot of scanning. Either way, it looks like something was being possibly worked on, but I can't find the post with final declaration of status.

I doubt it would help. HU should also handle events. Even if you add this by hand it would probably break (not respond) when phone will try to open events channel/send events...

Since with the touch tweak, touchscreen is active while driving using Mazda Connect, I'm not sure how by intercepting the 0x02 inputsource being sent to AA and changing it to 0x03 for touch/rotary would break things. If touch is not supported on either end even with this, wouldn't it just ignore screen touches and continue to function with rotary? I'm not trying to be obtuse here - I'm truly trying to understand the functionality.

Tehan said on 4/5/25,
"I read once on a random google thread about AA that Mazda tells AA to not respond to touch events. I am hoping that we can bypass this."

I had also read that somewhere (perhaps the same thread). So that's why I am asking about this. If this implementation of the Mazda connect code absolutely just doesn't send any touch output to AA that's one thing and this is absolutely dead. But if it does send touch output and the only reason that AA doesn't do anything with it is because it is being told to just accept rotary controls, that is another.

I leave this in your, and others, capable hands to determine whether or not to look further into this.

Thank you.

[Hawkweber]

From Snirpo:

If touch doesn't work with a wired connection (which I'm pretty sure of is the case with these cars), it's extremely unlikely it's going to work by hacking into the AA protocol.

If the only reason why touch doesn't work with AA is because the HU is telling AA not to respond to touch and only use rotary, then it would make sense that it doesn't work for either wired or wireless and there is a possibility of making it work by telling AA to respond to touch. Of course if the HU doesn't send touch output at all, then it is a dead option.