Redmi A1 (ice): factory reset + update to latest MIUI via fastboot (clean install) + lock bootloader

Factory reset 

I will do the factory reset from official recovery. To do this I have to enter first the recovery mode. From MIUI and with USB debugging enabled and phone connected to PC, I enter this command on PC:

abd reboot fastboot

The phone reboots to fastbootd mode where I will choose Enter recovery and then, in recovery mode I will select Wipe data/factory reset.

Update to latest MIUI via fastboot

After the factory reset is done, I will reboot to fastboot and flash the latest official global ROM for the phone via MiFlash.

Locking the bootloader

After the installation is complete, I will lock the bootloader following the mtkclient instructions:

1. Enter BROM mode and bypass it
2. Enter python mtk e metadata,userdata,md_udc
3. And finally, to lock the bootloader python mtk da seccfg lock
4. Reboot the phone