Last week I installed the new firmware (version 3179) on Bravia KD-55X8509C to fix the problem with slow remote control response.

Since then I have been unable to select 3D mode (either side-by-side or over-under). It appears to select it, but when you go Back it turns it off again.

Has anyone else experienced this?  I have reported this to Sony Customer Support  but all I get is stupid emails asking me to do a factory reset, disconnect external devices, install latest firmware, etc, etc.