I dont know. I think that you have to flash twrp by fastboot and then reboot in recovery, wipe all and flash xiaomi.eu.Hello paolo, i've tried lineageOS, it's very cool but, for me it's to hard for now I want to flash xiaomi.eu. How can i do that correctly? Hope on your answer.
I suggest you to try for some day lineage, It Is more clean than miui and battery performs about 20-30% more than miui. Try lineage, when you are sure wipe all and reflash from 0 lineage...