I'm from Brazil and in the last two days I was reading about the Android 9 Pie update to our Mi A2.
I also read that today it started to roll out to India and some European countries.
For curiosity I installed ExpressVPN, conected to an Holland server and tried to download the OTA. It worked flawlessly.
I flashed via fastboot the Magisk patched boot of 10.0.1 build and got the Magisk also working flawlessly.
For the Camera2 API, I just edited the Magisk module and added the line "persist.vendor.camera.HAL3.enabled=1". Then I installed it through Magisk module screen. It also worked.
These are the steps I did:
1 - Obviously you will need to be on Android 9 Pie
(Try to download the OTA via VPN or wait to get it in your country)
2 - Download this file and extract it: https: // drive.google.com/open?id=1b9jRc1gZuPJatds5RkuCiJtuE7UCH5wh
(Remove the spaces)
3 - Turn your phone off and boot it in Fastboot Mode by pressing and holding Power + Vol Down and then, plug into the USB;
4 - In the extracted files, open the folder "Plataform Tools" and then open the Power Shell window.
(Inside this folder I added the original "boot.img" and the "patched_boot.img", all from 10.0.1 build)
5 - In PowerShell, just type: fastboot boot patched_boot.img
(It should boot with Magisk installed)
6 - Open Magisk, tap Install and chose to install directly. Reboot
(It will prevent Magisk get uninstalled after reboot)
7 - Transfer the files "Camera 2 API Enabler - Pie.zip" and "Google Camera - 5.1.018 Arnova8G2 8.3b1 (Pie).apk" to your phone memory.
8 - Open Magisk, go to "Modules", then tap the yellow buttom, search for the "Camera 2 API Enabler - Pie.zip" file and then install it. Reboot
9 - Once the phone rebooted, install the "Google Camera - 5.1.018 Arnova8G2 8.3b1 (Pie).apk".
(Go to Developer Options and unchek "camera.enable_micro", so you can use 5MP on front camera)
10 - Done! You're now on Android Pie with Magisk and Google Camera