Here’s a detailed guide on how to check status of bootloader (locked or unlocked) on your Xiaomi Redmi Note 4X Android phone and then flash TWRP custom recovery using fastboot mode.
Flash TWRP custom recovery via fastboot on Redmi Note 4X
Download adb-windows.zip and extract to “C:\adb”.
Download TWRP recovery, for example twrp-3.1.0-0-mido-fix.img and copy recovery .img file to “C:\adb”.
Boot your device in fastboot mode(Press and hold “Power” button and “Volume -” until you’ll see fastboot mode logo) and connect your device to PC.
On your PC open “Device manager” to check the connection. If your phone is found and identified as “Android ADB Interface”, if you see only question marks then download and install ADB driver v1.17 lite.
Now go to “C:\adb” folder and press Shift + Right mouse button to open context menu and click on “Open terminal window”.
Now type this line to check device connection:
If device is connected correctly you’ll see unique identification number, if connection wasn’t successful you’ll see “waiting device” message.
Now we want to check if we got locked or unlocked bootloader. To check bootloader status on Redmi Note 4X, type this line:
fastboot oem device-info
If “device unlocked: true“ you’ve got unlocked bootloader, if “device unlocked: false” you’ve got locked bootloader.
To continue with installing TWRP recovery make sure your device is connected successfully and bootloader is unlocked, then type this command to flash TWRP .img file (twrp-3.1.0-0-mido-fix.img in this case):
fastboot flash recovery twrp-3.1.0-0-mido-fix.img
If you’re flashing another TWRP version, make sure to write correct file name!
Press “Enter” to start flashing.
After TWRP recovery is installed, don’t boot into the system, and boot in recovery mode first: press and hold “Power” and “Volume +” buttons and wait for 10-15 seconds for custom recovery to start.