HELP ME, I Can't update new room on my phone


Sorry all friends, i cant attack file log. I was try up room 8.12.27 and my phone black screen in all. Fastboot and android, i was seach in google and used miflash. Now my phone can use :D, but now room is: 8.10.25 eu develop (i try up to 8.11.1 but have some error:(. Now i want ask all my friends: How to up room 8.12.27 eu develop for mi5x. Thanks all my friends:D.