Follow up from
my post on 21.11.17. I saw
this interesting comment from
@LosTigeros and I tried to follow the steps he provided. Like him, I own a Mi 9T Pro and I was using version 20.12.9 Beta (MIUI 12.3, Android 10 QKQ1.190825.002) (which is now around a year old).
1. I made a backup of everything just in case
2. Dirty flash from 20.12.9 Beta to 21.11.17 Beta, clearing dalvik/cache. Upgrade worked fine and the phone booted normally after a few minutes on the MIUI logo screen
3. Dirty flash from 21.11.17 Beta to latest stable (xiaomi.eu_multi_HMK20ProMI9TPro_V12.5.6.0.RFKCNXM_v12-11.zip), clearing dalvik/cache again. Same as above.
Everything I use on a daily basis seems to work fine. I've only encountered a problem launching the Xiaomi Gallery app (version 2.3.1.7), it just crashes. Third party gallery apps work fine. I've noticed that this seem to be a known bug (as reported on various posts/threads) and I'm looking into a solution (clearing the cache didn't solve the issue and it's not possible to clear the app data).
Thanks again to
@LosTigeros for trying this solution and reporting it on the forums and to
@geoorg for his help and various suggestions