Here are the detailed steps to get rid of the ComServer, and get the signal back without full flashing.
1. Put the phone into bootloader/fastboot mode (Vol Down + Power)
2.Check if the phone is in fact connected properly by typing this while inside the fastboot folder:
fastboot devices
You're supposed to see something like "xxxxxxxxxx fastboot", if not you must fix the connection first.
3. Download this Comserver_Fix.exe PC app and run it.
You are supposed to see something like "Erasing 0.02s" then the phone should reboot automatically, and the ComServer gone.
https://drive.google.com/open?id=1g2..._f5hq4vFBHkpjE
Enjoy!
Thanks to Resident2011