With a release date in 2018 I expected to have my Xiaomi Mi Mix 3 at least for a few years – if I manage not to crush it like its predecessor. Already in 2020 I had to learn that Xiaomi stopped support for the former flagship device. Really very disappointing and not a big motivation to follow the Xiaomi flagship in the future.
It took me until beginning of 2022 to decide that I don’t want to buy a new device just because of misssing updates. At least not if there are proper custom roms out there that are still maintained. I found that Arrow OS is maintaining a branch for my phone with an updated Android 11. So i wanted to give it a try.
WARNING: Unlocking the bootloader removes all data from your device – it’s a factory reset!! So backup your data first!
The first big hurdle you need to take with Xiaomi is the bootloader. Under https://en.miui.com/unlock/download_en.html they provide a tool where you need to ask for permission to unlock your bootloader. The tool states theses steps to do:
- Download the Mi Unlock app to PC, and sign in with your Mi Account;
- Shut down your phone manually, and hold Volume down key and Power button to enter Fastboot mode;
- Connect your phone to PC using USB cable and click “Unlock”.
Also make sure to have the developer mode incl. the usb debugging enabled.
For being able to use fastboot under Windows I had to install the USB drivers for my phone first. I took the file from https://droidfilehost.com/download/download-xiaomi-usb-driver-for-windows/. After the installation nothin was changed but I was able to select the driver for the “Android” device from the list of predefined devices – “Android Composite ADB Interface”.
It is important that you are logged in to the same Xiaomi account in the unlock tool as you are logged in in your phone. Otherwise it won’t work because Xiaomi asks you to wait for 14 days to rethink your decision to unlock the device.
With the driver in place and the phone in fastboot mode the unlock tool finally recognised the phone and allowed me to klick unlock after having waited for the cooldown phase.
Install Arrow OS
Adb and fastboot come with Android Studio which I had already installed. So I took these tools simply from there. Further I downloaded the latest official release from Arrow OS – https://arrowos.net/download. Vanilla + Gapps build. Next to this we need a new recovery. So I also fetched the latest TWRP from https://dl.twrp.me/perseus/. The installation procedure is described under https://forum.xda-developers.com/t/rom-11-0-0-perseus-arrowos-11-0-official-weekly.4176405/#post-83706165 but that only gives directions and won’t help you if you don’t know the commands.
// start phone in fastboot mode (power + sound down = bootloader)
// install TWRP
fastboot flash recovery twrp.img
// reboot into recovery - (power + sound up = recovery)
fastboot reboot recovery
// wait until TWRP is started and allow it to do changes to the fs
// "Make FULL WIPE (system/vendor/data/dalvik/cache) and FORMAT DATA - YES" from within TWRP.
// copy downloaded files from my computer to the device
adb push vanilla.zip /sdcard/vanilla.zip
adb push gapps.zip /sdcard/gapps.zip
// install vanilla.zip via TWRP
// install gapps.zip via TWRP
// reboot device
The device should now boot into Arrow OS and up to now I haven’t found any problems.
In general the installation procedure for a custom rom hasn’t really changed so my experience from experimenting with my old Nexus 3 helped a lot avoiding to brick my device.
Important: I wrote this post from memory because I didn’t want to start from scratch to document it. Please write me if I missed something important or something is wrong. If you decide to follow the steps described in this post you do so on your own risk.