Release Notes:
Download both restore.suprx and renpdrm.skprx;
Copy these 2 files to ur0:tai/ (using FTP or USB or any way);
Open ux0:tai/config.txt if this file exists, or else ur0:tai/config.txt;
Under *ALL line, write : ur0:tai/restore.suprx
Under *KERNEL line, write : ur0:tai/renpdrm.skprx
Save the file
Reboot PSVita;
You can now use the PSStore and activate your PSVita from the Settings app under PlayStation Network.
Remarks
If you have nonpdrm.skprx inside config.txt, try removing it then reboot PSVita.