The tool will extract the system.img and vbmeta.img . FixFirmware patches the FRP logic inside these files.
If you are stuck on a device you purchased second-hand, the most reliable "fix" is to contact the original owner and have them remove the device from their Google account management page. fixfirmware frp bypass
You followed the guide, but you hit a wall. Here are the top 3 errors and fixes: The tool will extract the system