The device was a prototype IoT gateway powered by a MediaTek MTK chipset. It was supposed to speak to Windows 10 over USB, presenting itself as a standard Ethernet adapter. Instead, Windows saw a ghost.
Leo couldn’t change the firmware—the MTK chip was already in mass production. He had to write a custom INF file that would force Windows to bind its generic usbnet driver to the MediaTek’s specific Vendor ID (0x0E8D) and Product ID.
On Day 51, Leo plugged in the gateway. The yellow icon flickered. For one second, it turned into a spinning wheel. Then:
But it wasn't enough. Windows 10’s driver signing enforcement was the final boss. Leo had to boot into "Disable Driver Signature Enforcement" or submit the driver to Microsoft’s Hardware Dev Center for attestation.
[MediaTek.AddReg] HKR, NDI, HardwareID, 0, "USB\VID_0E8D&PID_7663"
[USB_Install.NT] Include = netnet.inf Needs = UsbNet.Client AddReg = MediaTek.AddReg
Windows 10 ships with cdc_ecm.inf , but it’s notoriously picky. It demands exact interface associations and will reject the device if the endpoint descriptors are one byte off. Leo’s gateway had three interfaces: a control interface, a data interface, and a third for debugging. Windows saw the third interface and threw a "Code 10" error: Device cannot start .
He closed the Device Manager, leaned back, and whispered to the empty lab: "Handshake accepted."