It didn’t take long for Yifan Lu’s investigations to become useful for other hardware hackers! Our community member katsu, guided by Yifan’s precise description of the Vita’s NAND pinouts, was able to hack his PS Vita in order to boot from a previous firmware, technically performing something very similar to a downgrade. Check the video below, it’s cool and full of “electronics ***”, like your favorite cyberpunk movie.

What katsu did was dump his firmware 2.12 (on the NAND), probably using Yifan Lu’s technique. He then copied that Firmware dump to an SD card. In the meantime, he upgraded the PS Vita to firmware 3.01. On the video, you see him inserting his SD card in a reader connected to the Vita. The Vita then reads the content of the SD card (the firmware 2.12 he dumped earlier) instead of its own 3.01 NAND.

What the heck does all of that mean? First of all, that Yifan Lu’s little experiment in the hardware world is proving successful, by providing inspiration and documentation for other talented hardware modders.

Secondly, that downgrading a PS Vita is a possibility under certain conditions: what the experience proves here is that technically your Vita is able to go back to a firmware that was previously installed on it. This might sound obvious, but it means that installing firmware 3.01 did not “change” anything that would make the Vita backward incompatible with its previous firmwares. That’s something that eventually Sony could change, but for now this is promising.

Now don’t get me wrong, this doesn’t mean downgrading a Vita will become mainstream overnight! The hardware modifications required here are pretty big for now, and more importantly, this would only work with a NAND dump of your own Vita, as it is very likely that the NAND encryption key is specific to each console. One wouldn’t be able to downgrade to someone else’s firmware. What this means though is that today, someone with cheap hardware and the required skills could dump their Vita 3.01 NAND, upgrade to Sony’s next firmware to get all the benefit of the PSN, and boot from firmware 3.01 again whenever they feel like running Total_Noob’s Custom Firmware again.

Here again, I am making this sound a bit better than it really is. Katsu did not prove it was possible to write anything back to the NAND, just that he is booting the firmware from an external reader, which according to him takes 10 minutes. Not something very practical for now.

Nevertheless, this is pretty exciting, and could be the first (second?) step in some cool Vita hardware hacks. Let’s see how this develops!

Source: katsu on /talk