Hi, I had the same problem on my 2010 Flex Ltd, no nav. It happened after a very cold spell of -40f for a few days. I would only get Sound Designed by Sony. No radio, or blue tooth or clock. Heat and cooling still worked and the ext temp and compass worked as shown above.
I drove around for a month thinking I need to get a new radio but at 360k miles I was not sure I wanted to invest anymore. I looked up the fuses and just removed 28 and 39, 20amp and 5amp and then re-installed them, and it started up like normal. It has been working again like normal since. I just googled Ford Flex 2010 fuse box diagram to find which fuses were which.
I drove around for a month thinking I need to get a new radio but at 360k miles I was not sure I wanted to invest anymore. I looked up the fuses and just removed 28 and 39, 20amp and 5amp and then re-installed them, and it started up like normal. It has been working again like normal since. I just googled Ford Flex 2010 fuse box diagram to find which fuses were which.