No more Test Point Method needed
Redmi Note 3 support rebooting to EDL in Android Bootloader aboot module (the "reboot-edl" command) but fastboot utility doesn't recognize "reboot-edl" in the command line and refuses to sent the command to the device. Since FastBoot command protocol is simple and text-based, it is enough to send a packet containing "reboot-edl" text over USB. The simplest way to do that is to patch Windows fastboot.exe file, replacing "reboot-bootloader" text with "reboot-edl". As "reboot-bootloader" string is found in the command line, fastboot.exe sends the same constant string to the device. So if "reboot-bootloader" is replaced with "reboot-edl", you can specify "reboot-edl" in the command line and the same text will be sent to the device.
New Update: Fastboot updated to latest version.
1. Download the Fastboot_edl-v2.zip from Here.
2. Extract the zip in your desktop
3. Open the folder and double Click on Reboot.bat
4. Reboot your device to Fastboot Mode by pressing
Vol Down + Power button and connect your device with PC and Press Enter.
5. Your Device will be rebooted to EDL!
6. Now flash your Fastboot Rom with Mi Flash Tool to Unbrick your Mi Note 3.
Thanks to @emuzychenko for the Idea!