The error is essentially a communication breakdown. Most users can solve this by updating their restoration software or ensuring they have the GSM-specific firmware for the iPhone 7.
If you are seeing the specific error message you are likely deep in the weeds of iOS restoration, jailbreaking, or using custom restoration tools like FutureRestore. loader for iphone9 3d101ap not found
: A damaged cable or a low-power USB port (such as one on a keyboard or a hub) can cause data packets to drop, leading the computer to "lose" the device during the critical loading phase. The error is essentially a communication breakdown