Press and on the TV (not the remote) while plugging the power cord back in.
If you have all the parts of the RAR archive, you must extract them to get a single file (usually named Update.img or V8-S586T02-LF1V371.bin ) before following these general steps: Format a USB drive to FAT32 . Download S586T02 LF1V371 part01 rar
Release the button once the firmware update progress bar appears on the screen. Press and on the TV (not the remote)