There's a trick to it if you can access a friend's updated Vita. Let me get home instead of phoneposting and I'll write up a quick tut.
EDIT: OK, here is the guide for if you own both a hacked and updated Vita.
http://pastebin.com/HtFZDGzT
Made originally for 3.61, but works the same for 3.63 or whatever.
A Vita can only have one PSN account registered to it at a time, and it must match the one for the memory card too.
If you can borrow a friend's Vita and want to use it to move a PSP demo to your 3.60 Vita, you should do the following.
- Eject any memory card in your friend's Vita.
- Format the Vita. Use the "Restore This System" option.
- Log in to your PSN account on their Vita.
- Do the steps under the heading "Deleting a 3.61 id.dat" for their memory card.
- Download to their memory card your PSP demo.
- On your own Vita, use QCMA to backup the PSP demo to your computer.
- Delete ux0:id.dat on their memory card and power your console off.
- Restore their Vita's system, then put their memory card back in. Your friend can have his Vita back and should be able to log in to PSN to access all his memory card contents again.
- Use QCMA to copy the PSP demo to your console on your own memory card.