MIUI Global Beta ROM 6.3.17 based on Android 6.0 Marshmallow has been started rolling out for Xiaomi Mi4 / Mi3 and Mi Note flagship smartphones. Users on older version 5.12.17 can directly update to MIUI Global Beta ROM 6.3.17 using the Updater app. If you’re on other versions, then no need to worry as we have shared a complete tutorial to install Marshmallow based global beta rom 6.3.17 on Mi4/3 and Mi Note.
Before proceeding with the below flashing tutorial, make sure to backup all your important data including SMS, call logs, app data, videos, contacts, calendars, etc. and also install USB Drivers on your PC. Charge your device up to 80% or more and make sure to enable USB Debugging mode from settings.
For more details about the update and changelog, do refer the below source link.
How to flash Marshmallow-based MIUI Global Beta Fastboot ROM 6.3.17 on Xiaomi Mi 4/3 & Mi Note
Step 1: Firstly you need to download MIUI ROM Flashing tool and fastboot rom from the below download section. Now extract the files on your Windows computer.
Step 2: Turn off the device and enter into fastboot mode. Pressing volume key + power button together will boot your device into fastboot mode.
Step 3: Then connect your device with Windows PC/laptop using a standard USB cable.
Step 4: Go to file folder of extracted ROM pack and copy its path.
Step 5: Install the MIUI flashing tool on your PC. Once done with installation, launch MiFlash.exe and paste the rom path which you have copied in the above step.
Step 6: Next you need to tap on “Refresh” button on Mi Flash which automatically recognize your Mi smartphone. Once recognized, tap on “Flash” button to start the flashing process.
Step 7: Wait until the flashing process is completed. Once done, your device will automatically boots into new version.
If the above guide didn’t worked for you, then try to flash the ROM using Mi PC Suite.
Mi 3 / Mi 4 Fastboot rom (1082MB) – Download
Mi Note Fastboot rom (1080MB) – Download
MIUI ROM Flashing tool
Source: MIUi Forum