If you read my piece on how I was able through the use of a PS3 able to install the "Turbo" Level of LittleBigPlanet PSP actually on my PSP. But it also meant changing the registration of my PSP, which only became a problem once it hit me "What about my old PSN account?". Let me tell you why I have 2 PSN accounts, I had one previously but it was pulled by Sony after their site was hacked. I was one of 1000s of people who suddenly had no PSN account. Really this was not an issue after Sony shut down its PSP servers. I really had only a couple of pennies in the account at the time it was closed. But now it's an issue, you see back in 2012 I have downloaded several PSP and PS1 titles really nothing more than just a handful of games 6 PS1 and 4 PSP games. The PS1 games are no issue, in fact out of the 6 there is only 1 I play regularly, as for the PSP games there are 2 I need to get an actual copy, nothing all that expensive. But the real problem is the demos I have quite a few that are no longer available as if this posting I have no idea the number that is currently unplayable.
My only advice is really if you're in the same position get another PSP specifically for PSN I wish I did that, oh what a mess I have gotten myself into.
Which only leaves the DLC, thankfully I can get what I no longer have access easily, most of what I use is free and is currently available through PSN. Which only leaves the pay DLC from Toy Story 3 PSP. Surprisingly I am not going to get it, for the reason those exact same levels are in the PS2 version right from the start and I do own a PS2 to play them on.