Originally Posted by smartyn13r
reverted to stock using
I have tried with this method but still showing "Open COM port fails, please check if other programs are using the COM port [Diagnostics]! ! !" when i'm trying to download the firmware.
try to use the remove drivers exe file
connect phone and Check for any installed drivers if found uninstall by checking the option delete drivers through device manager
make sure your PC has only one version of drivers for the phone
restart PC and install drivers
and follow the given link