[WretchedRefuse]

Unfortunately, for G-series you must use one of the three approved adapters for the initial unlock/flash: xHP Flashtool, Thor, or MHD. The web page does not list Amazon as a supplier for any of them. The online reviewers were probably flashing F-series cars with your "Amazon" adapter.

Having done some additional reading on the subject, it seems that the MHD UNI Wi-Fi adapter is the best because it supports the widest number of tools. Don't confuse it with other MHD adapters - they make several.

If you have a nearby Flashpoint, you can get it done there and avoid the wait for the adapter. You no longer need one of the specific adapters after it's been flashed the first time.