: This is almost always a driver issue. Reinstall the LibUSB-Win32 drivers provided in the UnlockTool folder.
If you are reading this, you are likely staring at a frustrating error message on your screen: inside the UnlockTool software. Your heart sinks. You have the device connected, the drivers are installed, and yet—nothing. The tool cannot identify or load the necessary bootloader for the specific motherboard variant of your iPhone 7. : This is almost always a driver issue
If the issue persists after following the steps above: the drivers are installed