[Xiaomi Mi 8 Questions & Answers] tsongming:
This issue didn't come from Xiaomi.EU.

First this exact issue has happened on practically every brand of phone that can use custom roms. next, both of my parents have a Mi8 and they have only used Xiaomi.EU. and have never used any other ROM. Not once has their phones had any kind of persist issue. My phone and my brothers phone have both had persist mount failure issues, several times. However, because we keep a backup of the persist restore and system boot with us at all times these issues can usually be repaired in 5 minutes.

At the moment I suspect that the persist problem could have originated from the Magisk Mi8 TTL module. In fact, just yesterday I installed it and for the first time I noticed that it downloaded and attempted to install a dummy image which helps it achieve its desired conclusion. That module may work for some but it seems to no longer work for the mi8.

Unfortunately, I deleted the dummy module. I actually thought that it came from a virus at first because when I copied files over to my PC. Windows reported virus in a flashable ringtones module, that is how i noticed it. ( it was not flagged)

After googling the modules. I found a few that contain a script to erase modems, Interesting! I don't know for certain where the dummy image came from, But my phone froze immediately after installing that module and then I began backing up files and found the dummy image file.

The flashable TWRP repair files that I made will restore persist for some people, and allow the phone to function again. But it is by no means not a permanent solution. if it worked immediately make your persist backup with the recommend TWRP. Now you have a long term solution.

It also seems that you may able to repair persist permanently by not using Magisk and relocking the bootloader. Perhaps after unlocking the bootloader a second time, phones that previously had persist issues can join the people who have never had persist issues ( the majority of users) ??????

Finally, just because some people reported persist in the Xiaomi.EU threads first doesn't mean that it came from there. Although everything is possible. Personally, I know that a majority of Mi8 custom Rom users use Xiaomi.EU as evidenced in polls on Telegram,4PDA and Mi Community.

If there was a link, then a lot more people would report this issue. Although I mentioned the TTL module, to be clear I don't think anything malicious is happening, persist problems is likely an unwanted byproduct. I recently encrypted my phone by accident testing custom roms, and when I flashed a different paid custom Miui Rom ( not Xiaomi.EU) I had a persist error.

So I restored persist and then restored all partitions via flashall.bat, as usual. At the end of the day, I see the persist issue once every 2 months on average. If I stopped flashing every week it would possibly never return.

If someone has an unbootable phone that is dead and they cannot boot to the system then steps on this thread will probably work, and if needed using my TWRP flashable persist files are safe and may work. What is not safe is flashing/restoring someone else's persist.bak file.

That’s it.

However, If you have ever used someone else's restore then you are lost with no solution except for spoofing, which i will not support.

PS

I think that may have figured out how to unbrick hard bricked phones with locked bootloaders. At the moment it’s only a theory, one that I am surprised no one else has thought of yet. At the moment, I will not elaborate. However, if anyone has a unrepairable bricked Mi8 or any recent bricked Xiaomi phone and you are willing to send it to me to experiment with, I will attempt to repair at no cost and return to you. Of Course you would need to pay shipping both ways.

One more thing

The same goes for anyone with a persist issue, so bad that you cannot boot to anything except for fast boot. This I am certain that I can fix. FYI: there will be a very small fee. Send me a PM if interested. (Do not send PM's asking for remote support any additional advice concerning persist issues will only be given on this thread.)