You tried to flash/root the Note 4X and failed. As a result, the phone becomes dead boot and can't turn on at all. Trying to enter Fastboot and EDL Mode using Deep Flash Cable did not work.
Frustrated! Do not know what to do to make phone back to normal.
Don't panic, you can do a test point with purpose making the device go into EDL Mode condition then flashed with MIUI ROM.
- See the location of test point Xiaomi Redmi Note 4X Snapdragon on image attachments below.
- Remove back case.
- Connect phone to PC using USB Cable. I assume the Qualcomm driver is already installed on your computer.
- Connect point to point as in the image using tweezers.
- Ensure HS-USB QDLoader 9008 detected on Ports Windows Device Manager.
- Flash using MI Flash Tool.