I have been searching the site for my exact problem, but cannot find it. I see similar issues and have tried the fixes, but to no avail.
1. My F90bt has been working fine and then yesterday, I got the Splash screen then black screen shutdown. None of the buttons are lit up, but I can hear the fan blowing as well.
2. Pushing the buttons after a while doesn't do anything either.
3. I tried the reboot with testmode (downloaded and unzipped the testmode zip file from this site, took the 2 folders and put them on my sd card). When I put in my sd card in my HU all the screen will do i