No, every time you update or restore to stock firmware you will always lose your JB. The JB is not permanent. And probably if you update you wont be able to JB untethered for a while till they release new JB programs. In other words you never update to stock firmware if you want to keep your JB. You wait till there's a JB for the new firmware and update then and rejailbreak. Or go stock, up to you.