1. Unlock Bootloader (Xiaomi procedure, 7 days via MI Unlock tool)2. Fastboot flash recovery TWRP and root the android 9 rom(based on https://www.cyanogenmods.org/forums/...rooting-guide/ 2.1 Install ADB for Windows and Xiaomi Drivers2.2 Download TWRP for MI MIX3 5G Android 9 PIE - twrp-3.3.1-0-andromeda.img(based on https://forum.xda-developers.com/sho....php?t=3941867 2.3 Rename file to recovery.img and put it into ADB folder on Windows2.4 Turn off the phone, Reboot to Fastboot (Volume Down + Power)2.5 Plug the phone into computer2.6 Open Windows CMD2.7 Go to your ADB directory2.8 Type the commands in cmdcd C:/adbfastboot devicesfastboot flash recovery recovery.img2.9 Download Disable Force Encryption and Magisk Zip2.10 Copy the files to USB memory stick formatted to FAT32, you should have two files:Magisk-v20.3.zipDisableForceEncryption_Treble.zip2.10 Turn on phone to recovery (Volume Up + Power)2.11 Go to Menu > Wipe > Format Data > "yes" (this will format the data)2.12 Go to Menu > Advanced > Fix Contents2.13 Plug in your USB stick with files via OTG USB C connector2.14 Go to Menu > Install > Select Storage > OTG2.15 Select Magisk-v20.3.zip2.16 Add more zips and select DisableForceEncryption_Treble.zip2.17 Flash the zips and reboot deviceTo gain root you may now only boot the recovery instead of flashing and proceed with flashing Magisk and Disable Force Encryption.# fastboot boot recovery.imgTWRP 3.3.1-1 Xiaomi Mi Mix 3 5G (andromeda) by mauronofrio:- Added Android 10 Support;- Fixed compatibility.zip errors;- Make the TWRP able to boot directly from fastboot;- Removed TWRP app;- Added dtbo and persist target to flash image menu;- Fixed some problems with Stock ROMs flashing.Download TWRP: https://androidfilehost.com/?fid=4349826312261701065 Thanks to @ mauronofrio (based on https://forum.xda-developers.com/one...owifi-t3934227 1.1 DownloadQPST_2.7.474.zipQUD.WIN.1.1 Installer-10037.3 Setup.zipJust use the standard settings and click on OK, next,1.2 OPEN DIAGNOSTIC PORT FOR THE SESSION FOR QPST (WINDOWS CMD ADB)cd C:/adbadb devicesadb shellsu (you need to add root permisions on android screen)setprop sys.usb.config diag,serial_cdev,rmnet,adb1.3 Once The Port is up you can use your Qualcomm Tools.1.4 For example you can change the VOLTE/VOWIFI settings with PDC ToolSelect your device, right click on "Commercial" and deactivate Sub0 and Sub1Click on Oversea-Commercial_DS again and click on remove -- DO NOT CLICK REMOVE, JUST DE-ACTIVATE IT - your settings stick after a reboot, so no longer need to remove the profile (at least on my device my profiles stick, also makes it easier to go back to default)cd C:/adbadb devicesadb shellsu (you need to add root permisions on android screen)setprop persist.dbg.ims_volte_enable 1; setprop persist.dbg.volte_avail_ovr 1; setprop persist.dbg.vt_avail_ovr 1; setprop persist.dbg.wfc_avail_ovr 11. Diagnostic codes:*#*#6484#*#*2. Testing*#*#4636#*#*3. Calendar*#*#225#*#*4. Google Play services*#*#426#*#*5. Rlz Debug Ul.*#*#759#*#*6. Imei Information*#06#Enter these codes into the Dialer to enable the options in Settings. (Settings < SIM Cards & mobile networks < Sim Card Settings < VoLTE Enabled/Make Calls using WLAN) . THEY ARE ENABLED BY DEFAULTVoLTE *#*#86583#*#*VoWIFI *#*#869434#*#*01. You need to have unlocked bootloader02. Download latest ROM based on your model (mine is 5G EEA n78)Mi MIX 3 5G EEA Stable Fastboot V10.3.21.0.PEMEUXM 9.0 Download 2.5 GB03. Download Mi Flash Tool04. Open the Mi Flash Tool, install drivers (if the install fails go to Mi Flash directory and create folder logs and log; open app again and install drivers)05. Unpack the rom fastboot tgz06. Select the Folder where the rom is unpacked (it should containg numerous of flash files)07. Tick the Clear Data at the bottom (don't choose the clear data and lock cause it will lock your bootloader again)08. Turn off the phone, Reboot to Fastboot (Volume Down + Power)09. Plug the phone into computer10. Click refresh, phone should be visible11. Click flash12. After successfull flash there could be an error fastboot lock (don't bother since you want to be unlocked)13. If you want root flash twrp and magisk again