I have a PSP Slim, with CFW 5.00 M33-6
I use to have a 4 gig card, and recently upraded it to a 16Gig Pro Duo Mark2 (authentic Sony card). I formatted it no problem, the PSP recognises 15 gig but that's cool as the translated space is most likely rounded off to 15 rather the 16.
The issue that I have though, is when I copy games on to it (in the ISO folder) some of my games won't work -- they work fine on the 4 Gig but no go on the 16.
Anyone else have this issue?