[cisco-voip] 7970s dark after phoneload update

[Robert Kulagowski]

> Anyone have a idea on why this happens on some phones on firmware
> updates? I see this mostly on 7970s. Customer had done DST related
> CCM updates, etc and when some of the phones took firmware update ,
> most came back ok. Some are dark and not powered up, and unplugging
> the ethernet and plugging it back in fixes them and they come back
> and work fine.

You may want to check whether they're really hung or just sitting there 
doing the update with the backlight turned off.

When I did my mass update to 8.2(1), I thought I had bricked 30 phones 
until I noticed that if looked at the screen at an oblique angle, you 
could see that stuff was happening.

Not sure why the backlight was off.