[Android General] wishie197:
Let's start with the 7-inch version.

First, I tried to tackle the broken Play Store. Generally speaking, people will suggest downloading OpenGApps and using TWRP to flash them. Unfortunately because this device is some random no-name device from China, it would be nearly impossible to find a working TWRP recovery for it. So flashing OpenGApps via a custom recovery is out of the question. Thankfully, there are other ways.

Installing the Play Store

First we need to enable 'USB Debugging' which can be found in 'Developer options' part of the Settings app within Android.

Open 'Settings' app, scroll down and select 'System' and then 'About tablet'

Once there, look for 'Build Number' and quickly tape on it 10 times or so until you see 'You are now a developer'

Back out of that menu and you should now see a new 'Developer options' section.

Inside 'Developer options' there is a setting labelled 'USB debugging'. Enable it.

Connect your tablet to your PC using a micro-USB cable.

Now we need to use ADB to install a few APKs to the device. If you don't have ADB installed on your computer, now is a good time to do it. Search this forum for information on how to do so.

The following APKs are needed, and should be installed in this order:

com.google.android.gsf.login

com.google.android.gsf

com.google.android.gms

com.android.vending

Obtain those APKs from your favourite APK repository and install them using '

adb install <filename>

'. Once all 4 are installed, the Play Store should be working. If not, reboot for good measure. I will attach a list of the specific versions of the APKs I installed.

Now you can install the Home Assistant companion app (or another browser of your choice, such as Fully Kiosk) and away you go, right? Well, sort of.

Since this tablet comes with an old/outdated version of Android WebView you are likely to get rendering/display issues in both the HA app, and Fully Kiosk app. Both of these use the configured 'Android WebView' option found in 'Developer options'. Unfortunately, in this ROM, that value has been hardcoded to use 'com.android.webview' package, which is a system app and not updatable from the Play Store. The Play Store 'Android WebView' is actually 'com.google.android.webview' and is not in the list of allowed 'Android WebView' options for this device. So I had two options. Firstly, ask the device manufacturer to make an updated ROM that allows other WebView implementations, or, try and modify if myself.

Updating (Installing alternative) Android WebView

The first method I tried was to install a newer 'com.android.webview' into /system/ which ended in failure... The tablet didn't appreciate this, and got stuck on next boot. Do not try this.

The second method I tried was to modify /system/framework/framework-res.apk to include alternative WebView implementations. This also failed. Do not try this.

The third method I tried was installing Xposed Framework, so that I can modify the WebView options that way. This method usually requires a custom recovery such as TWRP, which we do not have. Here is what we have to do instead:

Download the xposed-v90-sdk27-arm.tar from here

Download the XposedInstaller_3.1.5.apk attached to this post.

Use adb on your PC to copy it to the device

adb push xposed-v90-sdk27-arm.tar /sdcard/Download/

Use adb on your PC to install the XposedInstaller apk

adb install XposedInstaller_3.1.5.apk

Open an adb shell

adb shell

and switch to root by typing

su

Remount the /system filesystem (may not be needed as the install script may do this)

mount -o rw,remount /system

Extract the xposed-v90-sdk27-arm.tar file

tar -xvf xposed-v90-sdk27-arm.tar

Change into the directory that was just created

cd xposed-v90-sdk27-arm

Make the installer script executable

chmod a+x flash-script.sh

and run it

./flash-script.sh

Xposed Framework is now installed, but not activated. Reboot your device. Please note, it will take longer to boot than usual on the first boot.

Once your device has rebooted, open the Xposed Installed app and make sure it is activated. If it's orange and says its not activated, another reboot should sort it.

Once you have confirmed it is activated, we need to install a module called 'Any WebView'. Click on the Hamburger Menu, tap 'Download' and use the search to look for an install 'Any WebView'. Reboot your device.

Now, we need to install an updated Android WebView. You can install any compatible webview such as 'Google Chrome' or 'Android WebView' from the Play Store.

Go back into Settings->Developer options, select 'WebView Implementation' and choose your newly installed WebView. Do not use 'Android System WebView 61.0.x' as it is outdated.

Congratulations! You can now install the HA app, Fully Kiosk app, or anything else you need from the Play Store.

Here are some images of my 7 inch device displayed the Home Assistant Lovelace UI in Fully Kiosk Browser.