Miui 8


I don't know, when I upgraded I wiped everything, except the storage.
Maybe works if you wipe System and Cache only, maybe not. (In TWRP).

You must have the bootloader unlocked.
 
Internal Storage means your data, photos, music, porn , etc.
Data means your apps and settings.

so, when you upgrade from miui 8.0.1 to 8.0.2 for example, if you format only system, you don't lose anything. IF your phone ain't encrypted. If is encrypted, everything will be wiped out.
So yes, check if your phone is encrypted, delete only system and see if works.

Form lower 8 to higher 8 works. From 7 to 8 I did not tried :)
 
okay i successfully flashed miui8 now.
but my battery is draining much faster than before. Why is that?
 
e.g. when i have my phone in standby mode. With miui7 i lost in 2 Hours 1-3% in miui8 now 6-10%

At onscreen tasks it feels like that it drains faster than before. At the end of the day i usually got 50-40% left now i have 25-15% left and i'm doing the same tasks as before.

But i think that i will stick it Miui8. I really like the new notification bar and it feels a bit smoother.
 
Try to activate the power saving mods of miui. It have 2 mods. I noticed too that in miui7 the battery last longer ...
 
When i use whatsapp for 5-10 minutes i lose 8-10% that is crazy

Do you mean the new battery saver mode?

Do you think that i can achieve a better battery life with the official global rom ?
 
You can try. I have miui8 EU too but I don't lose energy that fast. Anyway, try that thing with restrict apps in background, in settings, power settings.