For some, one of the biggest selling points of Xiaomi is their willingness to allow the community to modify their phones. Other companies have done it in the past, but often, sooner or later, they get locked down. Huawei is a notable example of this, and if they had an unlocked bootloader you could flash the phone and never have to worry about Google preventing access to updates (not that it is an issue anymore).
For me, it has been many years since I installed a custom ROM on a phone, so the Mi 9T is a perfect time to try it.
What is an unlocked bootloader?
The bootloader term explains itself quite well, this is a program that starts whenever a device is powered on to activate the right operating system.
This is something that happens on most/all devices with an OS including Windows and Macs. If you have ever dual booted a PC it is the bootloader that allows you to choose the OS. Similarly, for Android, it is the bootloader that determines when to run Android or when to enter recovery mode.
Why install a custom ROM?
Installing a custom ROM isn't quite as widespread as it was, perhaps due to companies locking down their devices. In the earlier days of Android, it gave you more control over your device, this could be installing the latest OS, getting rid of ugly bloated skins and generally just optimising your phone.
Nowadays Android is more mature, for me at least there is less desire to install one. Android has matured a lot, and phones are considerably more powerful, I can't remember the last time I used a phone that was heavily bogged down and laggy.
That being said I am fortunate enough to update my phone regularly, for others installing a custom ROM allows you access to Android updates when the manufacturer ceases to do them. Sadly for some companies, updates stop sooner rather than later, so a custom ROM can be quite useful.
- A desktop or laptop PC
- Ensure that the phone is fully charged to avoid shutdowns during the process.
- Not a requirement, but you really should back anything important up. All photos, messages etc, as the contents of the phone will be deleted.
- USB cable – which you should already have
- You need to download ADB and Fastboot Tools to your PC and Extract it
- Download the Mi Flash Unlock tool
- Download the latest Xiaomi USB Drivers
How to unlock the bootloader
Please note that any modifications to your phone are at your own risk and this process may void your warranty.
- Enable Developer Mode by heading to the Settings> About Phone>Build Number and then tap it for seven times.
- Now, toggle USB Debugging mode, OEM unlock option by heading to the Developer Option.
- Before proceeding, head over to the Mi unlock site and click “Unlock Now” to apply for unlocking the bootloader.
- Type every information they need. Xiaomi will verify the device by sending the security code on your device to verify the actual owner.
- After applying, it will take 3-4 days to approve your application. Once you received the notification, you can proceed with the steps ahead. (Note: Steps Below should be performed after receiving application approval.)
- Download and Extract the Mi Flash Unlock tool on the PC.
- Upon extracting, open MiFlashUnlock.exe file from the folder and click Agree on the disclaimer page.
- Open the Mi Unlock tool and sign-in with the same Mi account you logged-in on the Mi 9T.
- Reboot your device into the Fastboot mode by pressing Power + Volume Down.
- Now, connect your Xiaomi Mi 9T with your PC via a USB cable.
- In the Mi Unlock Tool, you will see the “Unlock Now” option.
- Press the “Unlock Now” button, and the tool will automatically unlock the Mi 9T.
- Upon successful completion, you will get ‘Your device bootloader is unlocked‘ message.
- Restart the device and enjoy!
Xda-developers.com is probably your best source of custom ROMs, at least that's what I always used in the past. They have a dedicated Mi 9 ROMs section with several ROM options already.
Lineage OS is one of the most popular options and is the successor to the custom ROM CyanogenMod, at the moment this is not released, but I imagine it will be sooner or later.
Pixel Experience ROM is another popular option. As the name suggests, ROM brings the real Google Pixel Experience ROM on Xiaomi Mi 9. It has all the features and applications which comes out of the box with Google Pixel smartphone. It is available from here.
Similarly, crDroid is popular and is designed to increase performance and reliability over stock Android for your device also attempting to bringing many of the best features existent today. At the moment there is only an unofficial release but you can get it here.