Just so that everyone is on the same page and what your trying to achieve, what is your purpose of trying to make a dump of your legally own copy of Super Mario Galaxy?
Added Notes:
Using ddd to dump your WiiU games that is stored on your internal to external storage will only get you the Loadiine files, ie: Code, Content and Meta folders.
With these files you can only use it play on CEMU emulator on the PC or the WiiU homebrew app Loadiine GX2, the Loadiine files are stored and played from the SD CARD.
If you want your dump games to be WUP install files so you can re install at a later date in case the WiiU eShop shuts down, then you will need to repackage your Loadiine dump files to WUP file using NUSPacker.
Extra Notes:
Or you can stop all this piss farting around and try to get WiiU USB Helper installed, setup and working, then just download the game in WUP format. Dumped eShop games, like virtual console games, the tickets are fake signed so you will always need CFW to install and play, even if they are your legal copy.