This got me interested in the vita again.
Rebuilt the cable that I used back in 2017 (but somehow threw away when I stoped working on stuff in the vita scene..)
Used a female mini usb connector because it has those bent pins that make sure it makes contact. Also its very durable.
Already unplugged and replugged it like 50 times without breaking it.
To manufacture it just remove the shielding of the female usb mini connector and file it down from the side without pins
Was able to sand it down even more to make it fit even better
Next step will be to add a boostconverter to make it work without external power.. and maybe also create a 3dprinted shell for it to make it even more durable
Update:
Still has some issues - disconnects after mounting. will report back when fixed.
Update 2:
Turns out the power which can be delivered by the 3.3V rail from the vita is extremely low. By optimizing the circuit I used I could achieve filetransfers but not very stable.
My USB drive only used 0.02A during write. It was the only one out of 15 pcs that kinda worked.