I've had my Netgear Jetpack 791L mobile hotspot for many years and now when I turn it on, it cycles between the Netgear and orange Verizon screen. It never boots. What could be wrong? I've tried two other batteries, but get the same result. I've also tried draining the battery then charging it, but it doesn't matter how long I'd have it plugged in, I'd only get the black battery charging screen.
