As a matter of fact, Xiaomi never locks the Bootloader of Devices, but for Redmi Note 3 , Xiaomi locked the Bootloader. Xiaomi has clearly explained the key reasons for doing this in Xiaomi Forum.
The key reason mentioned by Xiaomi is ” in order to protect user data safety “. The other reasons are :
- To avoid fake Smartphones sold by Un-authorized Re-sellers. Many users have taken the risk of buying from a unofficial reseller. But they sometimes get fake Mi phones, or Mi phones with unofficial ROM loaded with bloatware.
- Another major issues, is Stolen Devices. Mi users have often encountered is that, after their Mi phones are lost or stolen , the person who got the device could easily flash a new ROM into it, and makes it almost impossible for our users to get their phones back.
The key changes which users have noticed after Bootloader is locked
- Locking bootloader will not affect normal OTA updates
- ROOT will be disabled if user has enabled it before. Enabling ROOT will need to unlock bootloader
- Recovery mode is changed. Updating via Recovery will need to use Mi PC Suite
- Devices with locked bootloader can not update using Miflash. Users need to unlock bootloader if they want to flash Fastboot ROMs.
Before we proceed, Please Note that , if you don’t know that much about Android, flashing, custom ROMs etc. It’s not recommended for you to unlock the bootloader. It might cause serious damage to your device or personal data.
What all you need before you unlock Bootloader
- Permission from Xiaomi for un-locking Device ( This process may take any where between 10 ~ 15 days )**
- A working Internet connection
- Mi Account logged in from Xiaomi Device
- Unlocking Tools
- The unlocking procedure only supports MIUI China developer version (6.1.12 or later version) currently. MIUI China stable version will get supported in future updates
** Permission from Xiaomi
1. After getting unlocking permission for a Mi account, users can unlock the verified device immediately. One Mi account could only unlock one device within 30 days
2. Users could require for unlocking permission in this site: http://en.miui.com/unlock/
3. If a prompt says that the current account is not logged into a connected device. Please log in with this account on the device that needs to be unlocked
4. If your device is encrypted, unlocking bootloader will wipe all user data. Please perform a backup beforehand5. If your application has been rejected, please try to apply again later. And please input the real reason that you want to unlock your device in Chinese or English. Don’t copy and paste others’ unlocking reasons.
The update will wipe all user data, please make backup beforehand
How to Unlock Bootloader
- Download zip file (recovery file) of China developer ROM for your device, put it into phone storage (If you’re using Redmi Note 3 Qualcomm version, you can unlock on MIUI Global Stable ROM, click here to download ).
- Go to Updater app, press the three dot on upper right corner, and select ‘Choose update package’. Choose the zip file you just put in phone storage.
- Log into the Mi account which has acquired unlocking permission on your device
- Turn off your device, press the Power button and Volume – button at the same time to enter bootloader mode
- Log into the unlocking tool on PC with the same Mi account. Connect the device with the PC using USB cable
- Press ‘Unlock’. The unlocking process will complete in about 10 seconds
After unlocking bootloader, users will be able to flash fastboot ROMs and custom ROMs. The unlocked device will be marked in the official service end. Users could lock bootloader again by flashing official MIUI ROMs. (This will need to use fastboot OEM lock. Please note to flash offcial MIUI ROMs, otherwise your system won’t be able to start).
You can also see the step by step procedure given by Xiaomi.
Source : Xiaomi