bootloader locked
when you try to unlock the bootloader with the miflash_unlock program, progress stops at 50% with an error:
" Couldnt verify device. Cant get info, connect again."

there is an opportunity to go into recovery and fastboot
there is an old version  of recovery (like the second one) without the "Connect with MiAssistant" item
I installed the Chinese version of the firmware with miui 10, rebooted the phone and caught bootloop