- Make a back up of your apps with Titanium backup (built-in backup does not work for apps when you downgrade and try to restore them)
- Download the full fastboot ROM at http://en.miui.com/download-37.html by clicking Download Full ROM in Developer section (or better click Flashing Guide in Developer section and then "Xiaomi Mi 2A Latest Developer Version Fastboot File Download"). There are also other fast boot ROMs for older ROMs available at http://en.miui.com/thread-14641-1-1.html
- Using MiFlash flash the downloaded ROM in fastboot (use flash_all_except_storage.bat script)
- Update back to MIUI Multi lang from xiaomi.eu using Updater app or Recovery.
- Restore data & apps (do not restore system settings!).