I have a Samsung 4K UHD TV (UE55RU7100KXXU).
I have downloaded the latest minor update and I do exactly as instructed. The usb stick is as it should be, according to the instructions. I put it in the USB slot, go to software update but it doesn't give me the option to update via the USB. It did before but now it seems I can only do it OTA.
Any ideas how I can update over USB without reseting the whole TV back to 'factory settings'?
Did you extract the file before dowloading it to your USB stick? Also, what's the current software version on your TV? Go to Home > Settings > Support > About This TV.