1) Download Qualcomm HS-USB driver

2) Download MiFlashTool (I tried several version)

3) Download latest Redmi 5 Plus China Stable ROM (Fastboot) – extract into a specific folder
Refer below link:-
global rom download

4) Install them & restart your PC in ‘disable driver signature enforcement’

5) 😱 Open up your back cover (Scariest part)
Use TEST POINT method to plug in my phone & detected as QUALCOMM HS-USB QDLoader 9008 under Ports 
Refer below:-

You may need to try several times**

6) After detected, open MiFlashTool, click refresh button & a COM number with a device detected

7) Select the folder where ROM being extracted, click FLASH & wait for firmware loaded into the phone.

Once done, power on the phone & all DONE, Red 5 Plus booted into original China ROM.

If want to install Global ROM, apply unlock permission legally & binding will surely be successful. But have to wait 360 hours to get the phone unlock.

Once unlocked, use MiFlashTool to install latest Global ROM (DO NOT use test point method 😬, plug into USB port as normal) in FASTBOOT mode.