An application to set your vita volume level without using the volume buttons (useful if they are broken) @theheroGAC completely rewrote the application to make it more modern and easy to use, all credits go to him!
Set the value you want, 0 being the lowest and 30 the maximum (25 for AVLS forced vitas) and then press square to reboot. You can also disable AVLS for a short while, it's basically a shortcut to the option you have in the settings app.
First you need the vitasdk installed on your computer.
Then go in the directory and type
cmake .
then
make
And if everything is setup properly you should get the vpk.