Update to 3.65 for Henkaku Enso, which is the coldboot exploit. 3.67+ does not currently support Enso, and until a new exploit is found may never. 3.65 still has access to PSN, so there's not real reason to update to 3.67+.
Update to 3.65 for Henkaku Enso, which is the coldboot exploit. 3.67+ does not currently support Enso, and until a new exploit is found may never. 3.65 still has access to PSN, so there's not real reason to update to 3.67+.
If you want better game compatibility, you can upgrade to 3.68, you just have to take an extra 15 seconds every boot to run h-encore manually. If you leave your vita in sleep all the time it doesn't really matter whether you have coldboot or not.