install third-party applications in the car head unit

Why not contact the manufacturer?

 

If the manufacturer has locked and/or disabled ADB in the firmware. I don't think there's much you can do about that, well not without rooting and hacking the unit somehow.

Does this head unit take removable storage, like SD cards or USB thumb-drives? If so, you could try putting the third-party app APKs on that, and try side-loading them that way, rather than trying to connect a computer.

Side-loading apps to an Android device via ADB using a computer. That's something I've never done.

 

I wouldn't bother trying to 'hack' into your head unit, with most vehicles the head unit is a fixed device (locked down) intended to be used for a limited number of purposes. They're not multi-functional mini PCs or anything like that, where the user tends to add/delete various software programs nor expansive services. A typical head unit is just a basic interface you use to interact with the vehicle's multimedia functionality.
I'm assuming the Android 9 install on that head unit is a locked, very stripped down, highly modified version of just the base Android OS.

 

What is the manufacturer of the vehicle?
Make, model, year, package?

 

From the OP's pics, it seems to a Kia factory fitted head-unit, Maybe recent, it has Kia's new marque

 

https://www.datanyze.com/companies/motrex/409507124

 

http://www.motrex.co.kr/

 

That pic of the device info has a QR code on the corner.

Use a QR code reader on your phone to scan it.

I tried finding the device online, but had mixed results.
Maybe the code will give a direct link.

Here is a simple QR code reader app.

https://f-droid.org/en/packages/de.markusfisch.android.binaryeye/

 

Given this is a secured (allegedly) device, locked down by its manufacturer, since you're attempting to hack into it you might be better off using reddit.com for solutions.

 

Ran across this article on how a streaming broadcast killed the radio in some Mazda cars. {This is only very indirectly related to the original posting of this thread. Probably more about the current, industry wide chip shortage.}
https://www.reviewgeek.com/109695/an-npr-broadcast-permanently-bricked-mazda-radio-systems/

 

But that's something that you shouldn't ignore. You're focused solely on tweaking some aspect to the head unit, but be sure it's a) readily replaceable if that's necessary, b) your 'hack' only affects to the head unit's functionality and this doesn't have any adverse issues with your vehicle's overall electrical infrastructure (you should contact your dealer to confirm that the head unit is essentially isolated from the rest of your vehicle's other electronic systems), and c) given the unit is locked down, if your vehicle is still within a warranty coverage period when you try to bypass any security measures will that nullify your coverage.

 

"...as it sent a broken image or file over the airwaves."

FWIW that sounds like a buffer overflow problem, that was probably corrupting the Mazda firmware. Which they were unable to fix with just software.

Hopefully this can never happen with self driving cars.

 

"hopefully"?

I think it already has.

If it does, would the media even report it?
That depends on if the vehicle manufacturer is a paying advertiser.

(Phizer (and others), here's looking at you!)

You know what they say...

Wish in one hand, and $#!+ in the other-
then tell me which one gets full first.

 

I'm sure the only things you might find on the main logic-board itself, might things like JTAG connections. Which is what the manufacturer uses in the factory for the initial firmware load, using their JTAG rigs. https://en.wikipedia.org/wiki/JTAG Plus maybe various test points, for testing and diagnostics using their whatever it is test kits.