And yes, you can use both the SD2Vita and the original memory card at the same time, but the second card can generally only be used for Adrenaline and emulators. You can't install Vita games to both, they can only be installed to the ux0 partition so if you wanted to use both for Vita games, then you'd have to keep swapping mount points whenever you wanted to play a game on either one of the cards.
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