It sounds as if you have to at least reflash the boot.img file, but you have to get into developer options first, and since the phone will no longer boot ...
You can try installing a Lenovo driver in a PC, then install
ADB and Fastboot Tool. Connect the phone to the PC and see if
fastboot devices
returns anything. If not, the phone is gone. If it does, try downloading a boot.img file for the phone (you'll probably have to download a stock ROM, then extract the file from the .zip) then try
fastboot reboot boot.img
If that brings the phone back, restart it (you'll get back to the "dead android) and try
fastboot flash boot boot.img
which should get the phone back.
If rebooting the file doesn't work, try the normal instructions for reflashing the entire ROM.
But, as I said, if the bootloader is still locked (flashing get_unlock_ability returns 0), you can't do anything with the phone unless you pay to have it JTAGed but that would cost more than replacing the phone.