@godreborn ,maybe it would take a firmware restore and an internal memory format,because i think the previous owner has messed up the whole PS Vita.
he can reinstall the firmware with qcma and its psv updates folder. that's what it's for. not sure about the same firmware unless it's possible through the recovery menu. he'd have to uninstall enso first which can be done with the installer. I've heard different things about whether or not a reinstall of the firmware is needed after uninstalling enso, so I'm not sure.