Press and hold the button on the TV itself (not the remote). While holding the button, plug the TV back in.
When your TV is unresponsive, a standard System Update via the menu isn't an option. Instead, you need to "flash" the firmware using a USB drive. Download 35017861 1920x1080 Konka KDL55XS715AN part4 rar
: The 35017861 firmware is designed for models with a 1920x1080 resolution panel. It fixes "boot loops" where the TV won't start past the loading screen. Press and hold the button on the TV itself (not the remote)
: Once you extract the .rar files, copy the main firmware file (usually named MstarUpgrade.bin or similar) directly to the root of your USB drive—do not put it in a folder. The Flash Process : Turn off the TV and unplug it from the wall. Insert the USB drive into the TV's USB port. Instead, you need to "flash" the firmware using a USB drive
: Use a 4GB or 8GB USB drive formatted to FAT32 .
Wait for a progress bar or "Software Updating" screen to appear, then release the button.