After some analysis it seems the latest Psvita official 2.60 firmware update did a little more than we thought.
With exploits, the amount of RAM available to use was limited to us to use. However, back in firmware 2.10 Sony cleared up that availability, whether intentionally or unintentionally, it allowed us to use more than normal. After that update it was possible to use around 64MB. Its unfortunate however, that with the latest firmware that space that allowed us to use the extra RAM is no longer available. So the summation is that TN-V4 will not be able to support the increased memory for 2.60 and above. However, this feature will be available to those under 2.60 when Total_Noob releases the new version of his CEF TN-V later.
So this is something that you’ll need to consider if you are thinking of updating from a previously released kernel exploit. Now, depending how porting goes for the new kernel exploit release it is completely possible to use the new exploit on current user mode releases to be able to use said memory increase features.
As for an estimated release date on TN-V4 (and possibly a kernel exploit); Total_Noob says that it will most likely be after the launch of the PS4. There are two reasons for this. One, is that TN is very busy and needs time to work on the release and straighten everything out. Another, is that we will most likely see another official Vita firmware update before the launch of the PS4, and that will probably be a very big update. That update (which should be 3.00) will most likely incorporate features for the PS4 such as Remote Play. Waiting until after, is the best option. As for the release of the PS4, there hasn’t been any word on that yet but my best bet is to say around late October/November.
Either way until then there will be some other goodies, and announcements. So, as always check back!