[Android Automotive OS] Tachi91:
This is a rant, but looking for ideas on getting ADB access or even better, root. Specifically to change the Phone Projection software or the one-sided restriction. Since there doesn't appear to be a concentrated source of information on these. Maybe we can start condensing it into a single thread.

General Motors Infotainment system with Google Built-in or otherwise known as gminfo37 [Chevrolet Infotainment 3 with Google Built-In]. First introduced I believe with the model year 2023 refreshes and has since been brought across the Chevrolet / GMC lineup, and Cadillac 🤷‍♂️? It's Android Automotive version 10 skinned for the respective brand.

[Hardware] - - RPO: IOK

There hasn't been much on what the underlying hardware besides this arstechnica article. I cannot find anything to indicate if the hardware is different across the vehicles or if it's all the same with various software changes. However, it is as follows. Unless someone else knows otherwise.

CPU: Intel Atom A3960 [Press Brief] [Tech Sheet] [CPU-ID]

iGPU: Intel HD 500

RAM: 6 GB

Storage: 64GB

Buttons that have access to the Infotainment.

Steering Wheel Buttons

- Voice/ Call Pick up

- Hangup

- Media Forward

- Media Back/Rewind

- Media Volume Up

- Media Volume Down

Infotainment Control Panel Buttons

- Home Key

- Volume Knob

- Power Button (Acts as Mute and if pressed and held.. Screensaver? Brings up Black screen with Time and Weather)

Nothing else seems to interact directly with the UI.

- While in park holding the hangup button for 10-15 seconds causes an Infotainment reboot.

Ports

- Center Console area 1x USB-C and 1x USB-A

- Arm Rest, 1x USB-C and 1x USB-A

[Software]

As it stands I'm using my vehicles software as of this writing.

Vehicle: 2024 Silverado 2500 HD

OS: Android Automative 10

Security Patch: Feb 5, 2023

Kernel: 4.19.207=PKT-211022T054706Z-ga6f15bcbba38-ab204 #1 Fri Mar 17 12:47:19 EDT 2023

Build: full_gminfo37_gb-user 10 W204E-Y169.3.2-QIHM22B-804.1 204 release-keys

Accepting all the risks of messing with a vehicles systems. It would be nice to see ADB side loading, maybe even root access. While you can access developer options and enable ADB. There's no usb passthrough to a PC for debugging etc.

GM has a developer portal where you request access. If someone were to get approved maybe they remotely enable usb debugging for custom app sideloading. However, I think it's more likely they'll simply have a website where you upload an .apk and they then forward it to the vehicle.

[RANT]

Spoiler content hidden.

[GOAL]

GM restricted Apple Carplay. My goal is to either try to edit the Projection .apks to remove the restriction or side-load a Carlink or similar .apk so that both CarPlay and Android Auto are given full-screen access. Right now enabling Developer Options in Settings doesn't amount to much. Enabling ADB doesn't expose it to either of the user facing USB Ports.

[IDEAS]

There are some payload like images that attempt to root your device. I'm still trying to trying to find one that's seems like it would work. AAOS does allow for mass storage media playback. I'm hoping that can be exploited to enable root or side load something.

I've tried random combination of buttons during a reboot attempting to enter recovery mode. I'm also thinking that maybe the HMI itself has a dedicated USB port for debugging. I've watched dash disassembly videos on YouTube that show the screen being removed. There are connections on the back, but I'm assuming those are for the separate console buttons (Hazards, HVAC etc) with one coming from the HMI itself for display. Typically the HMI is either hidden behind the glove box or within the center console somewhere.

Software tweaks, I'm thinging permissions, where Android can grant overlay "full-screen" per app if they request it or if defined in an .xml somewhere. Maybe this AAOS has allowed it for Android Projection, but not CarPlay. Assuming this isn't a single .apk with dual projection support, but two separate apps.

A few that might be the cause...

android.permission.SYSTEM_ALERT_WINDOW

Carlink sales a CCPA dongle that is used in tandem with their AutoKit app. If the preinstall projection apps can't be edited. Maybe Autokit can be side loaded, given overlay/full-screen permission. Then gain Wired and Wireless AA and CP via the dongle. Bypassing the built-in projection software and its limitations.

[Other Dongles]

The market is full of boxes that provide projection for various car models. However, the majority seem to rely on Carkit. They've spoofed the Apple CarPlay handshake so a vehicle would see an Apple Device attempting to show CarPlay. Which in this instance of GM's restriction won't grant full-screen.

It is apparently rare to find one of these dongles running Android AND presenting itself as Android Auto during the initial pairing handshake. The reddit thread linked above has the individual using one of these dongles. Where it spoofs the Android Auto handshake and then loads a custom launcher that presents a typical Android Homescreen. Thats how they're then able to install the AutoKit .apk and project onto the dongle itself. The others still load an Android home screen, but it's via "CarPlay" which is hindered.

I've reached out to GM via social media, but All I got was "I'll forward this concern to the appropriate team. Contact your local dealership for assistance" which means absolutely nothing. Corporate flip off.

But yea.. Anybody else has some insight or ideas?

Poking around and finding the HMI is on my to-do list. Randomly pressing more buttons during boot is also on there.

I'll add pictures and videos as I get the chance to sit still and take examples. Finding GM sourced pictures of CarPlay or Android Auto running is unsurprisingly nonexistent. Besides the reddit thread mentioned above. The only others I know of are behind private Facebook groups which I won't post here. I'll take some of my own when I get the chance.