I understand you're looking for information on a for an Alcor Micro USB repair tool specifically for the AU6989SN-GTC and AU6998SN controllers.
Remember: The tool is free, the knowledge is free, but your data is not. Always back up critical files. However, for those drives that have already failed and hold no critical data – or for cheap drives you want to experiment with – the Alcor MP Tool turns a brick back into a usable device. alcor micro usb repair tool au6989sngtc au6998sn free