I'm reverse engineering my 2021 RDX (software D.1.6.4) to get full-screen Android Auto. On the 2021 it's stuck in a narrower picture with black bars. The 2022–2025 RDX has it: Acura's bulletin B23066 says software F.1.4.1 "adds support for full screen CarPlay and Android Auto", but 2021 isn't covered and Acura won't update it.
I've already done a lot of groundwork on the 2021: I have ADB access, I've decompiled Honda's Android Auto receiver and found where the smaller video size is set, and I've cleared the side panel with a reversible display command. What I'm missing is Honda's newer receiver from a 2022+ unit to compare against. That would show me exactly how Acura changed it, and whether it can safely be done on a 2021.
What I need from a 2022+ owner who has ADB access to the head unit (all read-only, nothing on your car is changed):
- adb shell pm path com.honda.androidauto.projection.sink, and tell me the path it prints.
- adb pull the APK at that path, plus any other .apk in the same folder.
- adb pull the lib folder next to it (it contains libautoreceiver_jni.so).
- adb shell getprop ro.build.fingerprint
- adb shell dumpsys package com.honda.androidauto.projection.sink (the version lines are what matter).
- If you can, adb shell dumpsys window | grep -i -E "mOverscan|mStable|mRestricted" and a photo of Android Auto running full width.
How to get ADB on the head unit (this is how I did it on my 2021; the 2022+ menus may differ a little, so tell me if yours does):
- Ignition ON (or engine running), parked.
- Press and hold these three physical buttons under the touchpad at the same time: Back + Home + Track/Card. Hold about 3–5 seconds until a screen appears with Self-Diagnosis Mode and Detail Information & Setting (that's Dealer Diagnostics).
- Select Detail Information & Setting. On that screen, press and hold the same three buttons (the Track/Card button is the one that matters) for about 5 seconds. A hidden Developer Diagnostics list opens.
- Switch USB Mode Switch from Apple CarPlay to ADB. It's the first item in the list. This turns the head-unit USB port into an ADB port until you switch it back, so Android Auto and CarPlay won't work on that port in the meantime.
- Optional, for the normal Developer Options page: in that same list, scroll to the end and set Enable Developer Option. Then go to the regular Settings → System → About, tap Build Number 10 times, and a Developer Options line appears. Inside it, USB debugging does the same thing as step 4.
- Connect your computer with a USB cable to the head-unit port. On the first connection the car asks Allow USB debugging? and you accept on the car's screen.
- When you're done, set USB Mode Switch back to Apple CarPlay.
Careful: the Developer Diagnostics list contains items that can damage the unit, including Compulsion Loading, Factory Flashing, Bootloader Update and firmware updates. Don't touch those. Only use USB Mode Switch (and Enable Developer Option).
Please don't send a VIN, serial numbers, phone info or anything personal. None of the above contains any, but glance over before sharing. Please don't flash, delete or change anything on your car.
I'll share what I learn here, and I won't pass your files on to anyone else. If you don't have ADB access, even your Acura software version and a photo of Android Auto full-screen help. If you know how to reach the hidden developer or diagnostic menu on a 2022+ unit, tell me how you got there.
Thanks! Happy to answer questions and post my findings on the 2021 side.
EDIT
Also, if anyone has more experience with this or utilizing preexisting exploits, especially through codex or claude code please let me know!