I tried several times to update the software of my Philips 32PFL3517H12 Smart TV from T921E_2.02 to T921E_2.12 but it didn't work. When I start up the TV with the USB stick a few moments after the popup reading the update the TV turns black and nothing happens at all. I've tried the procedure several times with different USB-sticks, but nothing works.
How can I solve this problem and update the software properly ?

Fred