Damnit, now I can't stop thinking about ideas for Kyro... once you've got a direct connection into someone's mind, it seems a bit of a waste just to upload weapons.

"Woah, I know kung-fu... and how to repair a TX-456 engine core."

To keep that special for him on explain why Xiu-Xiu can't do it we just need technobabble! Let's see... Jacob's project designers were a lot less ethical, and didn't care about how much stress such a process might put on a human mind. Meanwhile Xiu-Xiu's team's first priority was preserving her mind in the transfer to nanites, so they emulate a human neural network as closely as possible, not able to access her mind beyond sensory inputs, usually in the form of a digital overlay.