Some clones are manufactured with that are "locked" and cannot be updated or recovered once the internal license is blacklisted. If the LED on the cable turns on immediately when plugged into a USB port (without being connected to a car), it may indicate a lower-quality clone that is more difficult to repair. Clone VCDS HEX- V2 Firmware Update Failed - Autonumen

If you’d like to move forward with the repair, let me know: What shows when plugged into the car? Does your PCB have an ARM STM32 chip or an ATMEGA chip? Are you comfortable using an ST-Link programmer ?

If it shows as a generic "USB Serial Port," the EEPROM is corrupted.

Disable your internet connection (or use a firewall to block the VCDS executable) to prevent the software from checking for official updates that might re-brick the device. Optimizing for "Extra Quality" Stability

: Ensure you are not running Windows in "S mode," as it prevents the installation of necessary drivers.