You might want to see if you have a valid warranty, so that you can ship it off to a SE service center. I used to have a K850i. And last I checked, there was no firmware updates or flash versions. Normally, when you get that situation with a SE phone that is either flashing or complete white screen, it would be suggested that you update the firmware through the Sony Ericsson Update Service, or flash the phone's firmware entirely. With the K850i, it seemed like SE left it stranded.