Hello, @ingbrzy
I've followed the steps mentioned here.
Unlocked bootloader;
Installed TWRP and Magisk using XiaoMiToolv2
Uploaded zip to internal storage (xiaomi.eu_multi_MI8_V12.5.1.0.QEACNXM_v12-10.zip) while on the TWRP recovery mode
Installed the zip plus wipped dalvik&cache
Rebooted...