[Security Discussion] farizadp:
Alright, I'm sharing my experience because I finally managed to install/run android navigation app on factory head unit of European 2015 Honda Jazz GK3 non-navi with the help from cmdroid.

Thanks to S_Mike and cmdroid team.

I've just bought second hand 2015 Honda Jazz GK3 on october 2019 without knowing what was programmed in the head unit from the previous owner.

I was really excited because I finally have a less-tech car yet I still can DIY the head unit. But then, I realized that honda factory head unit does not allow me to install any android apk.

Tried updating the built-in software/firmware through Honda connect (had my iPhone as an internet hotspot for the headunit) but the head-unit was just becoming more useless afterwards (think of only basic stuffs like audio, phones, rear cam work while I expected more from an android system).

I was about to buy the apple hdmi to lightning to connect my iPhone 8 but my gut is always telling me to not buy this hdmi lightning crap.

Head unit state before hacking.

- Menu, brightness, power combo buttons don't enter the diagnostic menu.

- Firmware version: 10.096.00.0021 (at this point I don't really care about the android version)

- By looking at this firmware version in the RC8 LHD xls list, I can determine that my head unit ID is 6YH3 at RC8.

- Installing apks from cmdroid always give me 'greyed Install button' even after renaming to HondaAppCenter_A1.apk.

When installing stuffs I always keep the following things in my mind.

- Make sure the engine is on, this is basic rule because if the head unit battery drains when installing stuffs the head unit might be screwed

- Park the car, transmission neutral, handbrake is engaged. Disengaging the handbrake or shifting gear to reverse triggers something in the head unit which I don't know (I don't want this interruptions during installing firmware).

- Try as much as possible to not do factory default during the entire steps unless I got stuck somewhere during installation.

The overview of the steps is described below.

1. Downgrade to RC6

2. Install HRV permissions app from cmdroid (I know the naming might be confusing, but it works in my EU 2015 Jazz GK3 non-navi)

3. Install waze, sygic, etc any apks available from cmdroid (use renaming trick to HondaAppCenter_A1.apk).

4. Add permissions for those apps through Honda permissions app

5. Upgrade to RC8 (because I would like to have some fixes which are available on RC8)

Downgrading to RC6

- Put the files in the RC6 LHD xls list into any FAT32 USB stick (Use your laptop or pc, whatever). Make sure only those files are in the root/main directory of the USB file system. For 6YH3 ADA_usbdl_V0E094000021_sec_14ada.zip, ADA_usbdl_V0C.091.01_T0AX_09.zip, AUD30CF.bin

- Insert this USB stick to the USB port below the head unit.

- Hit Menu, brightness, power combo until the head unit display goes off.

- The head unit will downgrade the firmware. Follow the instruction on the headunit display and pray that the the unit doesn't get bricked.

- This took me ~15mins until the head unit shows the warning message "it's the responsibility of driver to drive safely... bla bla bla" (excited at this point). Checked the firmware version: 0E.094.00.0021, which is good.

- At this point the downgrade succeeds. I'm able to install HRV permissions, install apks from cmdroid, get the waze, youtube, sygic, running on the head unit even with the handbrake disengaged (of course with changing the permissions first).

- Ohh, now the Menu, brightness, power combo also shows the diagnostic menu. Double happy !!

The upgrade procedure is also the same only I have to look at the RC8 LHD xls list to determine which files I need to place in USB stick (not to forget to delete the RC6 files first from the main/root of the USB stick).