yes, you can do it, but you need specific cIOS :
- Hermes cIOS v4 or v5.1
- D2x cIOS v9 (deprecated)
- d2x v10-alt (beta53) <-- recommended
With one if these cIOS, it lets you use USB Port0 and Port1.
USBLoadrGX has an option to mount both Ports at the same time (one after the other, but keeps list of game in memory to use proper port when you launch the game).
- Settings > Loader settings > Loader's IOS : select one slot where you have one of the cIOS listed above. and reload the loader.
- Settings > HDD settings > Port : Both
- Settings > HDD settings > Partition : All (to list all partitions from all USB Port at the same time)