I tried after reboot PC as well as phone with driver signature disable.maybe it is still working in background. for sure, reboot your pc and try again. As you say you successfully opened diag port, it must saw your phone. diag port is one way. can not connect 2 apps same time.
After clicking Install it's asking for "Press any key to continue" and after few seconds command prompt closed automatically.
I checked the Install.cmd file and found that it is also not having the word ADB after diag. Do I have to add and try?
Below is full text from Install file:
@Echo off
color 0A
echo ..................................
echo ...... VOLTE HACKER for RN3 ......
echo .. By mmengi, @amog787, @agritux..
echo ..................................
echo Do this at YOUR OWN RISK!
echo We are not responsible if you screw up.
set sim=1
set op=1
if %sim%==1 if %op%==1 (set efs=SIM1_AIRT)
echo ...........................
echo ...........................
echo Please grant Root authorization for your device
Tool\adb.exe shell "su -c setprop sys.usb.config diag"
pause
Tool\EfsTools.exe uploadDirectory -i EFS/%efs%/ -o /
pause