[Xiaomi Mi A2 Lite Questions & Answers] Halliwud:
Downgrade helped as of 30.05.2019

Mi A2 lite

Bought Galaxy Buds. Stuttered and eventually lost connection.

NOTE:What comes ahead is my personal experience (with some software errors that doesnt seem to have effect on our goal) downgrading my MI A2 lite to Oreo.

Downloaded Android Oreo 9.6.11 , ADB and Fastboot, Miflash(latest from site) from links in the beginning of the thread.

Very few proper video tutorials (Indian mostlyXD).

Enabled developer options on my phone (tapping 7 times on build number). In developer options enabled allow OEM unlock and turned on usb debug mode.

Turned off phone and launched it it fastboot mode (hold "volume down" and power button simultaneously). Connect phone to PC via usb.

Open folder on PC where you installed ADB and fastboot software. Launch cmd.exe or smth. In black window type "fastboot oem unlock" Enter. The phone reboots (takes a lot of time dont be alert) and wipes data from your phone. You will see a scary message/warning (disappear s after few sec) that asks you to lock bootloader back.

NOTE: somehow my device did not ask for any confirmations for enabling unlocked bootloader.

NOTE 2: I was trying to do this whole process by video and text guides. Some ppl type commands in cmd "fastboot flashing unlock" and then "fastboot flashing unlock_critical" BUT for some reason this commands did nothing. So all I did is oem unlock command.

After OEM unlock command rebooted phone skip all phone setups and open developer mode again (if it is locked) and in dev options check if "allow oem unlock" and usb debug mode is turned on. Turn off your phone and load it in fastboot mode (volume down+power).

On PC unpack Android Oreo files. It should look like a long name folder with some .bat files and folder (avoid unpacking in place with strange name paths).

Launch MiFlash tool. NOTE: it gave me a prompt for installing drivers and after i pressed it gave an error. It is fixed by creating inside MiFlash tool folder a new folder and naming it "log". Then launch the tool again and press install drivers.

Once you are in MiFlash program there is a ling space where you can insert a file path. You need to copy a file path that leads to your unpacked Android Oreo files (the path should lead inside where the .bat files located). Paste this copied path into MiFlash path bar and press refresh button. If there is no error you can proceed by pressing in the bottom right corner a "clear all" option and in the top right "flash" button. This will install Android Oreo on your mi a2 lite.

After the process is done i had an error in MiFlash program BUT the phone reboots on its own with downgraded Android version. Turn the phone off, load it in fastboot mode, connect via usb and run in ADB folder CMD.exe and run "fastboot oem lock" command. The phone reboots, takes a while.

!!!

After it reboots immediately skip all phone setup menus especially wifi and account options and go straight in settings to unlock developer mode. In developer options TURN OFF AUTOMATIC SYSTEM UPDATES! After it you can finish phone setup process ,accounts, networks and everything else.

An Android message "update available" can pop up. To get rid of it for good simply swipe it slowly A BIT (not all the way) till you see a cog sign (options icon) and there turn of this notification.

Now you can go smoke a cigar. Android 8.1.0 Oreo installed AND it wont update automaticlly to PIE. You can use your bluetooth devices properly (or whatever problems you had).

Have a nice day. Gonna probably go buy Samsung A30. This **** is unacceptable. Pie update rolled out long time ago (Android Q is releasing in 3 months from now) and this stuff is still not fixed. Wtf