This is a matter of patience sometimes. Did you read instructions carefully on the devices site?: https://devices.ubuntu-touch.io/device/jasmine-sprout/ Sometimes it can do the trick to repeat the installation, sometimes even several times.. In my case I didn't have to downgrade to android 9, but most of the cases it seems to be useful. Just try again, be patient and kind to yourself! maybe you want to read reports in the forum first, there are always some good hints to find: https://forums.ubports.com/category/92/xiaomi-mi-a2 good luck!