The Miracle Box hardware draws a specific voltage (usually 5V via USB). A standard PC port provides 500mA (USB 2.0) to 900mA (USB 3.0). When you connect a phone (for flashing) and the box on a single hub or a cheap motherboard, the voltage drops below 4.75V. The moment the voltage dips, the box microcontroller resets. Result? Unstable USB port.
USB Ports Not Working on Windows: Solve Common USB Issues | Dell US unstable usb port miracle box 2.82 solution