Like with many bugs on mi5 :)
but I wonder why is that. The problem seems to be software not a hardware.
Problem with not waking display I partially solved changing setting in battery options. Maybe the problem concerns
some sort of settings which I can't find?
When I don't answer an incoming call the ringtone volume increase gradual to maximum.
Next call ringtone volume increase to maximum or near the maximum from the first tone.
That change also ringtone volume settings in /sounds/volume/ringtone
which stays in increased position.
The same thing...
How to unlock bootloader first try on stable china rom if not work download and instal via updater app china dev
After unlocking look this forum for zip file rom for yours device
Tutorial on yours device
Is I wrote before safest way in my opinion is MiPc suite with recovery.
There are different options for example edl mode miflash but for me more risky (bootloop etc)
Find my threads on miui global I can't paste links cause miui global is temporarily closed.
China rom has eng language
Like said MannyRibo You need official china xiaomi rom to get bootloader unlocked. Unlocking tool will not verify Yours device with different rom.
Yours xiaomi.eu rom is not typical cause has no twrp. It was installed on blocked bootloader via edl command or miflash.
The problem is that...
Instal MISuite app on computer, run Misuite and connect your device in recovery (screen with the wire connected to the phone)
Misuite should find your phone check for update of china stable rom and install it (the latest one)
Sometimes there are problems with adb drivers try different computer...
After I installed on MI5 188.8.131.52 rom yesterday I'v noticed twice problem with calls - my interlocutors can't hear me. I have to disconnect and connect again.
On china roms problem never happened ( I used device with china rom for 4 weeks)
Is it possible that problem was caused by xiaomi.eu...