Hello! Upgrading your Redmi Note 9 Pro to MIUI 14 involves unlocking the bootloader, which allows you to install custom ROMs like MIUI 14. Here are the general steps to unlock the bootloader on your device:
1. Backup your data: Before proceeding, make sure to back up all your important data as unlocking the bootloader will erase all data on your device.
2. Enable Developer Options: Go to Settings > About phone > tap on MIUI version 7 times to enable Developer Options.
3. Enable OEM Unlocking: In Developer Options, enable OEM unlocking.
4. Request Unlocking Permission: Go to Xiaomi's official website and apply for bootloader unlocking permission. This process may take a few days.
5. Unlock the Bootloader: Once you receive permission, follow the official unlocking instructions provided by Xiaomi. This usually involves using the Mi Unlock Tool on a PC.
6. Flash MIUI 14 ROM: After unlocking the bootloader, you can download the MIUI 14 ROM for your device from trusted sources. Then, boot your device into TWRP recovery mode and flash the ROM.
Please note that unlocking the bootloader and installing custom ROMs may void your warranty and can potentially brick your device if not done correctly. Make sure to follow the instructions carefully and do thorough research before proceeding. If you're not comfortable with these steps, it's advisable to seek help from experienced users or professionals.