It's in the Adrenaline settings (video filtering), not the official settings. Just don't click open official menu, you might have to press L or R to switch to different pages.
If the Vita is blurry, then you didn't disable either Adrenaline filtering or official menu filtering.
let me get this right (sorry for bothering, am feeling dumb), this could be the problem: when i long press the ps vita button, on top there is the Adrenaline settings; inside that, there is: Main, States, Settings, and About.
inside the "Open official settings" under "Main" ive unchecked the tick "Bilinear Filtering"
when i press R, L, i can switch to different pages, under States there is the New state0, 1 2,3 etc.
next page is settings, inside is graphics filtering, smooth graphics, f.lux filter color etc etc, next is About page, in it is info and credits for Adrenline, so where is the video filtering option? or the
"you didn't disable either Adrenaline filtering or official menu filtering", where is this option? also may i ask what do you set for Graphics filtering option? like original, Bilinear, sharp bilinear, Advanced AA etc? thankyou