In USBLoaderGX go to the settings > credit, look at the top right. (this cIOS in the one used by the loader, not the games)
Then check Settings > Loader settings > Game IOS.
By default, the cIOs used by loaders is slot 249.
In that slot, you should have d2x cIOS v10 (beta52 or 53) with base 56.
if it’s not the case, try to reinstall d2x cIOS, or try another slot in the settings.